Secondary literature sources for the CALCITONIN domain

For each of the hand selected primary papers associated with the CALCITONIN domain, 100 neighbouring papers are retrieved from PubMed. If one of these neighbouring papers is referenced by more than two primary papers, it is shown in the table below.

Solution structure of tertiapin determined using nuclear magnetic resonance and distance geometry.

Xu X, Nelson JW
Proteins. 1993; 17: 124-37

The solution structure of tertiapin, a 21-residue bee venom peptide, has been characterized by circular dichroism (CD), two-dimensional nuclear magnetic resonance (NMR) spectroscopy, and distance geometry. A total of 21 lowest error structures were obtained from distance geometry calculations. Superimposition of these structures shows that the backbone of tertiapin is very well defined. One type-I reverse turn from residue 4 to 7 and an alpha-helix from residue 12 to 19 exist in the structure of tertiapin. The alpha-helical region is best defined from both conformational analysis and structural superimposition. The overall three-dimensional structure of tertiapin is highly compact resulting from side chain interactions. The structural information obtained from CD and NMR are compared for both tertiapin and apamin (ref. 3), another bee venom peptide. Tertiapin and apamin have some similar secondary structure, but display different tertiary structures.

[Calcitonin gene-related peptide and pain modulation]

Xu GY, Duanmu ZX, Yin QZ
Sheng Li Ke Xue Jin Zhan. 1993; 24: 67-9

[Calcitonin gene-related peptide]

Wu K
Sheng Li Ke Xue Jin Zhan. 1989; 20: 57-62

Calcitonin gene-related peptide and its receptors: molecular genetics, physiology, pathophysiology, and therapeutic potentials.

Wimalawansa SJ
Endocr Rev. 1996; 17: 533-85

NMR studies of lantibiotics. The structure of nisin in aqueous solution.

Van de Ven FJ, Van den Hooven HW, Konings RN, Hilbers CW
Eur J Biochem. 1991; 202: 1181-8

Nisin is a posttranslationally modified protein of 34 amino acids, and is a member of the class of bacteriocidal polypeptides known as lantibiotics, that contain the unusual amino acid lanthionine. Its structure in aqueous solution has been determined on the basis of NMR data, i.e. interproton distance constraints derived from nuclear Overhauser enhancement spectroscopy and torsion angle constraints derived from double-quantum-filtered correlated spectroscopy. Translation of the NMR constraints into a three-dimensional structure was carried out with the distance-geometry program DISMAN, followed by restrained energy minimization using CHARMm. The internal mobility of the peptide chain prohibited the determination of a precise overall folding of the molecule, but parts of the structure could be obtained, albeit sometimes with low resolution. The structure of nisin can best be defined as follows. The outermost N-terminal and C-terminal regions of nisin appear quite flexible, the remainder of the molecule consists of an amphiphilic N-terminal fragment (residues 3-19), joined by a flexible 'hinge' region to a rigid double-ring fragment formed by residues 23-28. The latter fragment has the appearance of a somewhat overwound alpha-helix. It is suggested, by assuming the presence of a (transient) alpha-helical structure in this part of prenisin, that the coupling between residues 23 and 26, as well as between 25 and 28, by thioether bridges, and the inversion of the C alpha chiralities at positions 23 and 25, can be rationalized.

Calcitonin gene-related peptide. Potential role in vascular disorders.

Shulkes A
Drugs Aging. 1993; 3: 189-94

Conformational studies of cyclic peptide structures in solution from 1H-Nmr data by distance geometry calculation and restrained energy minimization.

Senn H, Loosli HR, Sanner M, Braun W
Biopolymers. 1990; 29: 1387-400

The three-dimensional structure of a cyclic bouvardin analogue, cyclo (-Pro-MeTyr-Ala-MeTyr-MeTyr-D-Ala-) has been determined by distance geometry calculation and restrained energy minimization from nmr data. The preparation of the input for the distance geometry calculations, the modification of the amino acid library, and the analysis of the structures were done with the aid of a recently developed software package, GEOM. A great variety of different initial structures were explored to check the uniqueness of the determined solution structure. Calculations with 500 different initial structures and two different strategies led to a uniquely determined backbone conformation with a root mean square deviations value of 0.4 A. The backbone structure consists of two beta-turns, a beta-II turn at Pro1-MeTyr2, and a beta-VI turn at MeTyr4-MeTyr5. The efficiency of the two calculation strategies were compared in order to propose an optimal means for performing distance geometry calculations with cyclic structures.

Sequence-specific 1H NMR assignment and secondary structure of neuropeptide Y in aqueous solution.

Saudek V, Pelton JT
Biochemistry. 1990; 29: 4509-15

Sequence-specific assignment of the 1H NMR spectrum of the 36 amino acid polypeptide porcine neuropeptide Y (pNPY) at pH 3.1 is reported. It was achieved by use of standard two-dimensional techniques and by a combination of the sequential and main-chain-directed assignment strategies. The secondary structure was derived from inspection of the nuclear Overhauser spectra, slow hydrogen-deuterium exchange effects, chemical shifts of main-chain HA resonances, and coupling constants. These studies indicate that the C-terminal segment (residues 11-36) folds into an amphiphilic alpha-helix; the N-terminal segment, containing three prolines in both cis and trans conformations, assumes no regular structure. CD studies of pNPY at pH 3.1 and 7.4 show an increase in ordered structure at neutral pH. The difference spectrum, however, is typical of an alpha-helix and suggests a stabilization of residues 11-36, possibly via Maxfield-Scheraga pair interactions involving side-chain residues. This is supported by a comparison of the one-dimensional 1H NMR spectra of pNPY at pH 3.1 and 7.4, where no remarkable differences are observed.

Calcitonin and calcitonin gene-related peptide in the human brain.

Sagar SM, Henke H, Fischer JA
Psychopharmacol Bull. 1984; 20: 447-50

Solution structure of human corticotropin releasing factor by 1H NMR and distance geometry with restrained molecular dynamics.

Romier C, Bernassau JM, Cambillau C, Darbon H
Protein Eng. 1993; 6: 149-56

The structure of human corticotropin releasing factor (hCRF) has been determined by proton nuclear magnetic resonance (1H NMR) in a mixed-solvent system of 66% trifluoroethanol/34% H2O at pH 3.8 and 37 degrees C. Nearly complete resonance assignment was achieved by using standard two-dimensional methods. Distance restraints for structure calculations were obtained by qualitative analysis of intra- and inter-residue nuclear Overhauser effects. Structures were obtained from the distance restraints by distance geometry, followed by refinement using molecular dynamics and were completed with amide hydrogen exchange data. The structure of hCRF in this solvent comprises an extended N-terminal tetrapeptide connected to a well-defined alpha-helix between residues 6 and 36. The first half of the alpha-helix (residues 6-20) is clearly amphipathic. The five carboxy-terminal residues are predominantly disordered.

The conformation of endothelin-1 in aqueous solution: NMR-derived constraints combined with distance geometry and molecular dynamics calculations.

Reily MD, Dunbar JB Jr
Biochem Biophys Res Commun. 1991; 178: 570-7

The aqueous solution conformation of the bicyclic, 21 amino acid vasoconstrictor peptide, endothelin-1, has been determined using two dimensional NMR and a combination of distance geometry and molecular dynamics. The dominant structural feature is a helical region between Lys9 and Cys15 characterized by strong NHi-NHi+1 NOEs and several long range NOEs spanning 3 to 5 residues. Solvent inaccessibility and possible hydrogen bonding in the Cys3-Cys11 loop is suggested by the temperature independence of the chemical shifts of several amide protons. There is no evidence for association of the C-terminal hexapeptide with the bicyclic region.

Molecular pharmacology of receptors for calcitonin-gene-related peptide, amylin and adrenomedullin.

Poyner DR
Biochem Soc Trans. 1997; 25: 1032-6

Pharmacology of receptors for calcitonin gene-related peptide and amylin.

Poyner D
Trends Pharmacol Sci. 1995; 16: 424-8

Calcitonin gene-related peptide (CGRP), a widespread neuropeptide with multiple actions, has substantial homology with amylin, a peptide implicated in insulin-resistant diabetes, and adrenomedullin, a recently discovered potent vasodilator. There is controversy over the existence of CGRP receptor subtypes, and whether independent receptors exist for amylin and adrenomedullin. In this article, the current status of CGRP receptor classification is reviewed by David Poyner, taking particular account of species differences, and evidence is presented supporting the existence of multiple receptors for CGRP, as well as independent binding sites for amylin.

Solution structure of mu-conotoxin GIIIA analysed by 2D-NMR and distance geometry calculations.

Ott KH, Becker S, Gordon RD, Ruterjans H
FEBS Lett. 1991; 278: 160-6

We have investigated the structure of mu-conotoxin GIIIA by 2D-NMR methods. The assignment of 1H NMR spectra and a quantitative analysis of NOE and J-coupling data are presented. These results were used for the calculation of secondary structure elements of mu-conotoxin GIIIA. Distance geometry calculations were carried out to define the global folding of the peptide.

Studies on peptides. CXLII. Synthesis of des-1-Ala-des-alpha-amino-human calcitonin gene-related peptide.

Otaka A, Fujii N, Funakoshi S, Yamamoto I, Torizuka K, Noda T, Morita K, Yajima H
Chem Pharm Bull (Tokyo). 1986; 34: 3915-8

Release of calcitonin gene-related peptide from a human medullary carcinoma of the thyroid in vitro.

Ohashi M, Fujio N, Ibayashi H
Experientia. 1986; 42: 829-30

The secretion of human calcitonin gene-related peptide was examined in perifusates of medullary carcinoma of the thyroid with a sensitive radioreceptor assay. Calcitonin gene-related peptide was released after the addition of calcium (25-100 mM), in a dose-dependent manner. The results indicate that human medullary carcinomas of the thyroid secrete the calcitonin gene-related peptide as well as calcitonin.

Conformation analysis of eel calcitonin--comparison with the conformation of elcatonin.

Ogawa K, Nishimura S, Uchiyama S, Kobayashi K, Kyogoku Y, Hayashi M, Kobayashi Y
Eur J Biochem. 1998; 257: 331-6

The solution structure of eel calcitonin in a mixture of 60% water and 40% trifluoroethanol has been determined in this study by the combined use of 1H-NMR spectroscopy and distance geometry calculations. 1H-NMR spectroscopy provided 181 distance constraints, 5 dihedral angle constraints and 14 hydrogen bond constraints. The observed NOEs demonstrated the presence of an amphiphilic a-helix in position Leu4-Gln20. The seven best converged structures exhibit backbone atomic rmsd of 0.027 nm for the backbone atoms from the averaged coordinate position in the region of Cysl-Leu19. In the previous study [Ogawa, K., Nishimura, S., Doi, M., Kyogoku, Y., Hayashi, M. & Kobayashi, Y. (1994) Eur: J. Biochem. 222, 659-666], the conformation of elcatonin, an analogue of eel calcitonin, was characterized by an amphiphilic a-helix between Thr6 and Thr21 and a turn structure in the first five residues of the N-terminus. The major difference of structure between eel calcitonin and elcatonin exists within the cyclic moiety at the helical N-terminus. Some of the turn structure detected at the N-terminus in elcatonin is not found in eel calcitonin. This is attributed to the difference in the ring formation caused by the disulfide bridge and ethylene bridge. A medium-range NOE, dalphaN(i,i+2), is detected between the CalphaH of Arg24 and the NH of Asp26, so a turn structure occurs in this segment. This NOE connectivity profile in the C-terminal region is also the same in elcatonin, suggesting that this is important for receptor binding and immunological properties.

Solution conformation of endothelin, a potent vaso-constricting bicyclic peptide. A combined use of 1H NMR spectroscopy and distance geometry calculations.

Munro S, Craik D, McConville C, Hall J, Searle M, Bicknell W, Scanlon D, Chandler C
FEBS Lett. 1991; 278: 9-13

The solution structure of endothelin-1, a newly discovered potent bicyclic peptide vaso-constrictor agent, has been investigated using 1H NMR conformational constraints and distance geometry calculations. The conformation is constrained by two disulphide bridges between Cys1-Cys15 and Cys3-Cys11 but the NMR data and computed conformers show additional helical structure between residues Leu6 and Cys11. Our results are compared with previous conflicting reports on the solution conformation of this peptide.

Calcitonin, calcitonin gene-related peptide, adrenomedullin and amylin: homologous peptides, separate receptors and overlapping biological actions.

Muff R, Born W, Fischer JA
Eur J Endocrinol. 1995; 133: 17-20

Calcitonin, calcitonin gene-related peptide, adrenomedullin and amylin are structurally related peptides with N-terminal 6-7 amino acid ring structures linked by a disulfide bridge and with amidated C-termini. Among the related bioactive peptides, the structures of the calcitonin receptor and subtypes thereof have been identified so far through molecular cloning. Cross-reaction between receptors of calcitonin, calcitonin gene-related peptide, adrenomedullin and amylin, as well as overlapping biological actions, anticipate that the respective receptors belong to a family of G-protein-coupled receptors that include those of parathyroid hormone, secretin and vasointestinal peptide.

[CGRP or calcitonin gene-related peptide]

Moukhtar MS, Jullienne A
Rev Rhum Ed Fr. 1994; 61: 196-203

A 1H NMR study of human calcitonin in solution.

Motta A, Temussi PA, Wunsch E, Bovermann G
Biochemistry. 1991; 30: 2364-71

Human calcitonin (hCT) has been investigated by NMR at 400 MHz in DMSOd6 and in an 85% DMSOd6-15% 1H2O (v/v) cryoprotective mixture. All backbone and side-chain resonances have been assigned, and the secondary structure has been determined in both solvents. In DMSOd6, the simultaneous presence of d alpha N, dNN, and some specific weak medium-range nuclear Overhauser effects, together with the amide temperature coefficients and the analysis of the NH-alpha CH spin-spin coupling constants, indicates that hCT is highly flexible but with three domains (comprising segments Asn3-Gly10, Gln14-Thr21, and Thr25-Ala31) in extended conformations which dynamically transform into isolated beta turns in the N- and C-terminal regions and into adjacent tight turns, resembling a 3(10) helix structure, in the central part. The DMSO-water mixture rigidifies the polypeptide chain, favoring an ordered, extended conformation. NOESY data indicate the presence of a short double-stranded antiparallel beta sheet in the central region made by residues 16-21 and connected by a two-residue hairpin loop formed by residues 18 and 19. Two tight turns, formed by residues 3-6 and 28-31, were also identified. The central beta sheet does not favor an amphipathic distribution of the residues as found for salmon calcitonin [Motta, A., Castiglione Morelli, M. A., Goud, N., & Temussi, P. A. (1989) Biochemistry 28, 7998-8002]. This is in agreement with the smaller tendency of hCT to form the amphipathic alpha helix, postulated to be responsible for the interaction of hCT with lipids. The possible role of the cis-trans isomerism of Pro is discussed.

Solution structure of human calcitonin in membrane-mimetic environment: the role of the amphipathic helix.

Motta A, Andreotti G, Amodeo P, Strazzullo G, Castiglione Morelli MA
Proteins. 1998; 32: 314-23

The 32 amino acid hormone human calcitonin was studied at pH 3.7 and 7.4 by multidimensional NMR spectroscopy in sodium dodecyl sulfate micelles at 310K. The secondary structure was obtained from nuclear Overhauser enhancement spectroscopy (NOESY), 3JHNalpha coupling constants, and slowly exchanging amide data. Three-dimensional structures consistent with NMR data were generated by using distance geometry calculations. A set of 265 interproton distances derived from NOESY experiments, hydrogen-bond constraints obtained from amide exchange, and coupling constants were used. From the initial random conformations, 30 distance geometry structures with minimal violations were selected for further refinement with restrained energy minimization. In micelles, at both pHs, the hormone assumes an amphipathic alpha-helix from Leu9 to Phel6, followed by a type-I beta-turn between residues Phel6 and Phel9. From His20 onward the molecule is extended and no interaction with the helix was observed. The relevance of the amphipathic helix for the structure-activity relationship, the possible mechanisms of interaction with the receptor, as well as the formation of fibrillar aggregates, is discussed.

Isolation and partial characterization of the calcitonin gene in a lower vertebrate. Predicted structure of avian calcitonin gene-related peptide.

Minvielle S, Cressent M, Lasmoles F, Jullienne A, Milhaud G, Moukhtar MS
FEBS Lett. 1986; 203: 7-10

The gene coding for calcitonin was isolated and characterized in a non-mammalian vertebrate, chicken. Sequencing of the 3'-end of this gene revealed after the calcitonin coding exon, an intron followed by an exon coding for a calcitonin gene-related peptide, which displays significant amino acid sequence homology with mammalian CGRPs so far sequenced.

Conformational characterization by circular-dichroism spectroscopy of various fragments and analogs of calcitonin-gene-related peptide.

Mimeault M, St-Pierre S, Fournier A
Eur J Biochem. 1994; 222: 1063-1063

Solution structure of salmon calcitonin.

Meyer JP, Pelton JT, Hoflack J, Saudek V
Biopolymers. 1991; 31: 233-41

Salmon calcitonin, a 32-residue peptide with a 1-7 disulfide bridge, was synthesized by standard solid-phase techniques, and studied by CD and two-dimensional NMR experiments. The peptide was dissolved in pure trifluoroethanol (TFE) and in aqueous solutions containing various amounts of TFE. CD studies in pure TFE indicated the presence of an alpha-helical structure comprising 40% of the constituent amino acids. This was fully confirmed by nmr. A detailed analysis was performed with the peptide in a 9 : 1 deuterated TFE/H2O mixture. A total of 365 nuclear Overhauser enhancements (154 intraresidual, 112 sequential and 99 long range) were complied from the nuclear Overhauser enhancement spectroscopy spectra and used in the distance geometry calculations. The core of the peptide between residues 8 and 22 assumes an alpha-helix like structure. The Cys 1-Cys 7 ring is well defined and in close association with the helix, while the C-terminal decapeptide folds back toward the core, forming a loose loop.

Solution structure of a human calcitonin analog elucidated by NMR and distance geometry calculations.

Katahira R, Doi M, Kyogoku Y, Yamada-Nosaka A, Yamasaki K, Takai M, Kobayashi Y
Int J Pept Protein Res. 1995; 45: 305-11

Three-dimensional structure of a human calcitonin analog (abbreviated as hCTa) in which the amino acids of the wild type are replaced at position 12, 16 and 19 by leucine residues and further at position 22 by a tyrosine residue was studied in TFE solution by 1H-NMR and distance geometry calculations. This analog has a 15-20 times activity as compared with the wild type. The amino acid replacements resulted in formation of an amphiphilic alpha-helix in the region between the residues 4-20. The overall three-dimensional structure is similar to that of the wild type. The conformational feature of hCTa with a hydrophobic face composed with a Met and four Leu residues may be related to its higher hypocalcemic potency.

[Tissue distribution and physiologic role of calcitonin and CGRP]

Inaba M, Nishizawa Y, Morii H
Nippon Rinsho. 1990; 48: 1011-5

[Gene-related peptide in Raynaud phenomenon]

Harvald B
Ugeskr Laeger. 1993; 155: 3308-9

Calcitonin gene-related peptide--a new concept in receptor-ligand specificity?

Hall JM, Smith DM
Trends Pharmacol Sci. 1998; 19: 303-5

Constrained analogues of the calcitonin gene-related peptide.

Hakala JM, Valo T, Vihavainen S, Hermonen J, Heino P, Halme M, Koskinen AM
Biochem Biophys Res Commun. 1994; 202: 497-503

The calcitonin gene-related peptide, CGRP, has potential medicinal use for instance as a vasodilator or in the regulation of bone metabolism. In this study new analogues of CGRP based on molecular modelling of active fragments were synthesised and tested. The analogues were found to have affinities for the receptor comparable to those seen for native CGRP. Two analogues were found to be agonists. The analogues give an insight to the bioactive conformation of CGRP as they were constrained by disulphide bridges.

[Structure and regulation of the expression of calcitonin and CGRP genes and processing of the precursors]

Fujita T
Nippon Rinsho. 1989; 47: 2231-5

Studies on peptides. CLXII. Synthesis of chicken calcitonin-gene-related peptide (cCGRP) by application of sulfoxide-directed disulfide-bond-forming reaction.

Fujii N, Watanabe T, Aotake T, Otaka A, Yamamoto I, Konishi J, Yajima H
Chem Pharm Bull (Tokyo). 1988; 36: 3304-11

Calcitonin gene products: evolution, expression and biological targets.

Fischer JA, Born W
Bone Miner. 1987; 2: 347-59

Solution conformation of endothelin determined by nuclear magnetic resonance and distance geometry.

Endo S, Inooka H, Ishibashi Y, Kitada C, Mizuta E, Fujino M
FEBS Lett. 1989; 257: 149-54

The solution conformation of endothelium-derived vasoconstrictor peptide, endothelin, has been determined by two-dimensional 1H-NMR spectroscopy and distance geometry. Conformation in the N-terminal core region (residues 1-15) is well-defined and a characteristic is the helix-like conformation in the segment from Lys9 to Cys15. Contrarily, the C-terminal tail region (residues 16-21) does not assume a defined conformation and there are no specific interactions between the core and the tail regions.

Alopecia areata has low plasma levels of the vasodilator/immunomodulator calcitonin gene-related peptide.

Daly TJ
Arch Dermatol. 1998; 134: 1164-5

Amylin compared with calcitonin gene-related peptide: structure, biology, and relevance to metabolic disease.

Cooper GJ
Endocr Rev. 1994; 15: 163-201

Menopausal flushes and calcitonin-gene-related peptide.

Chen JT, Hirai Y, Seimiya Y, Hasumi K, Shiraki M
Lancet. 1993; 342: 49-49

Conformational study of cyclolinopeptide A. A distance geometry and molecular dynamics approach.

Castiglione Morelli MA, Pastore A, Pedone C, Temussi PA, Zanotti G, Tancredi T
Int J Pept Protein Res. 1991; 37: 81-9

The conformation of cyclolinopeptide A, c(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val), a naturally occurring peptide with remarkable cytoprotective activity, has been investigated by means of distance geometry calculations and molecular dynamics simulations. The starting points for all the calculations were an X-ray structure and other structures obtained from distance geometry calculations based on NMR data. Restrained and unrestrained molecular dynamics simulations are reported in vacuo and in CCl4. Structural and dynamic properties are investigated and compared with those experimentally determined. The conformation obtained from the MD simulations which best reproduces the NMR parameters is at the same time one of the most stable ones and is also fairly similar to the crystal structure. An explanation for the occurrence of multiple conformations in solution at room temperature is given.

Calcitonin gene-related peptide and Raynaud's phenomenon.

Bunker CB, Foreman JC, Dowd PM
Lancet. 1990; 335: 239-239

The physiology of calcitonin gene-related peptide in the islet compared with that of islet amyloid polypeptide (amylin).

Bretherton-Watt D, Ghatei MA, Jamal H, Gilbey SG, Jones PM, Bloom SR
Ann N Y Acad Sci. 1992; 657: 299-312

Following the discovery of a second gene containing a CGRP-like sequence, we demonstrated that "beta-CGRP" was indeed translated as a 37-amino acid peptide in vivo and was the predominant form of CGRP produced by the enteric nervous system. The presence of CGRP in the islet has been reported by several groups. We now show that beta-CGRP is again the major form. Another 37-amino acid peptide was recently isolated from islet amyloid deposits and found to have approximately 50% amino acid sequence homology with CGRP. Islet amyloid polypeptide, or amylin, is co-localized with insulin to the beta-cell secretory granule and is synthesized and released in parallel with insulin in response to a range of physiological and pharmacological stimuli. IAPP was subsequently shown, like CGRP, to inhibit the release of insulin pharmacologically. Interestingly, it was also shown to decrease the uptake of glucose by striated muscle, though it was considerably less potent than CGRP. This led to the suggestion that IAPP might be a circulating hormone regulating peripheral insulin sensitivity. Infusion of IAPP in human volunteers to produce plasma concentrations more than 100-fold higher than those seen physiologically, however, failed to alter peripheral glucose disposal. We conclude that beta-CGRP and IAPP are likely to play a role in local paracrine control of the islet.

Calcitonin gene-related peptide: vasoactive effects and potential therapeutic role.

Brain SD, Cambridge H
Gen Pharmacol. 1996; 27: 607-11

1. The cardiovascular biology of calcitonin gene-related peptide (CGRP) and the structurally related peptides amylin and adrenomedullin are briefly reviewed. 2. CGRP is a potent and long-lasting vasodilator; its possible role in disease, and the therapeutic potential of CGRP receptor agonists and antagonists is discussed.

Solution three-dimensional structure of surfactin: a cyclic lipopeptide studied by 1H-NMR, distance geometry, and molecular dynamics.

Bonmatin JM, Genest M, Labbe H, Ptak M
Biopolymers. 1994; 34: 975-86

The solution three-dimensional structure of the protonated [Leu7]-surfactin, an heptapeptide extracted from Bacillus subtilis, has been determined from two-dimensional 1H-nmr performed in 2H6-dimethylsulfoxide and combined with molecular modeling. Experimental data included 9 coupling constants, 61 nuclear Overhauser effect derived distances, NH temperature coefficients, and 13C relaxation times. Two distance geometry (DISMAN) protocols converged toward models of the structure and the best of them were refined by restrained and unrestrained molecular dynamics (GROMOS). Two structures in accord with the set of experimental constraints are presented. Both are characterized by a "horse saddle" topology for ring atoms on which are attached the two polar Glu and Asp side chains showing an orientation clearly opposite to that of the C11-13 aliphatic chain. Amphipathic and surface properties of surfactin are certainly related to the existence of such minor polar and a major hydrophobic domains. The particular "claw" configuration of acidic residues observed in surfactin gives important clues for the understanding of its cation binding and transporting ability.

NMR and dynamical simulated annealing studies on the solution conformation of urotensin II.

Bhaskaran R, Arunkumar AI, Yu C
Biochim Biophys Acta. 1994; 1199: 115-22

We determined the structure in solution of the vaso-constrictor hormone urotensin II (dodecapeptide) using nuclear magnetic resonance spectroscopy. Complete assignment of all proton resonances has been achieved and the structural information has been obtained from the interproton distance measurements derived from the nuclear Overhauser enhancement data. A combination of distance geometry and dynamical simulated annealing techniques was used to calculate the structure in solution. Nine resultant structures with fewer distance constraint violations were selected that satisfy the experimental restraints very well. The conformation of the molecule in the cyclic hexapeptide segment (core region) is well-defined whereas the N-terminal segment is disordered. This result correlates very well with the earlier predictions about the biologically active and inactive roles played by the core and the N-terminal segment respectively.

Calcitonin gene-related peptide in the cardiovascular system: characterization of receptor populations and their (patho)physiological significance.

Bell D, McDermott BJ
Pharmacol Rev. 1996; 48: 253-88

The structure of melittin. A 1H-NMR study in methanol.

Bazzo R, Tappin MJ, Pastore A, Harvey TS, Carver JA, Campbell ID
Eur J Biochem. 1988; 173: 139-46

The conformation of the 26-residue polypeptide melittin has been studied using 1H-NMR spectroscopy in methanolic solution. The 1H-NMR spectrum of melittin has been assigned using two-dimensional NMR techniques and the secondary structure has been calculated from nuclear Overhauser enhancement data using distance geometry and restrained molecular dynamics analyses. The structure is found to be mainly helical, and similar to that found in crystals from diffraction data: residues 2-11 and 13-26 form regular alpha-helices joined by a 'hinge' between residues 11-12. The structure in this hinge region is shown to be significantly different from that in the crystal structure, leading to a smaller angle between the two helices. The possible significance of the proline residues in this and similar membrane-spanning peptides is discussed.

The peptidergic motoneurone.

Arvidsson U, Piehl F, Johnson H, Ulfhake B, Cullheim S, Hokfelt T
Neuroreport. 1993; 4: 849-56

Acetylcholine is the classic transmitter in the spinal cord motoneurone. Recent studies have shown that motoneurones also contain calcitonin-gene related peptide (CGRP) and other peptides. In addition to transmitter-like effects, CGRP may also exert trophic actions, as suggested by changes in CGRP expression in motoneurones during development and following experimental perturbations.

Calcitonin gene-related peptide (CGRP) and amylin and the endocrine pancreas.

Ahren B, Pettersson M
Int J Pancreatol. 1990; 6: 1-15