Taxonomic distribution of proteins containing MbtH domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing MbtH domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

The 1.8 A crystal structure of PA2412, an MbtH-like protein from thepyoverdine cluster of Pseudomonas aeruginosa.

Drake EJ, Cao J, Qu J, Shah MB, Straubinger RM, Gulick AM
J Biol Chem. 2007; 282: 20425-34

Many bacteria use nonribosomal peptide synthetase (NRPS) proteins toproduce peptide antibiotics and siderophores. The catalytic domains of theNRPS proteins are usually linked in large multidomain proteins. Often,additional proteins are coexpressed with NRPS proteins that modify theNRPS peptide products, ensure the availability of substrate buildingblocks, or play a role in the import or export of the NRPS product. ManyNRPS clusters include a small protein of approximately 80 amino acids withhomology to the MbtH protein of mycobactin synthesis in Mycobacteriatuberculosis; no function has been assigned to these proteins. Pseudomonasaeruginosa utilizes an NRPS cluster to synthesize the siderophorepyoverdine. The pyoverdine peptide contains a dihydroxyquinoline-basedchromophore, as well as two formyl-N-hydroxyornithine residues, which areinvolved in iron binding. The pyoverdine cluster contains four modularNRPS enzymes and 10-15 additional proteins that are essential forpyoverdine production. Coexpressed with the pyoverdine synthetic enzymesis a 72-amino acid MbtH-like family member designated PA2412. We havedetermined the three-dimensional structure of the PA2412 protein anddescribe here the structure and the location of conserved regions.Additionally, we have further analyzed a deletion mutant of the PA2412protein for growth and pyoverdine production. Our results demonstrate thatPA2412 is necessary for the production or secretion of pyoverdine atnormal levels. The PA2412 deletion strain is able to use exogenouslyproduced pyoverdine, showing that there is no defect in the uptake orutilization of the iron-pyoverdine complex.

New knowledge from old: in silico discovery of novel protein domains inStreptomyces coelicolor.

Yeats C, Bentley S, Bateman A
BMC Microbiol. 2003; 3: 3-3

BACKGROUND: Streptomyces coelicolor has long been considered a remarkablebacterium with a complex life-cycle, ubiquitous environmentaldistribution, linear chromosomes and plasmids, and a huge range ofpharmaceutically useful secondary metabolites. Completion of the genomesequence demonstrated that this diversity carried through to the geneticlevel, with over 7000 genes identified. We sought to expand ourunderstanding of this organism at the molecular level throughidentification and annotation of novel protein domains. Protein domainsare the evolutionary conserved units from which proteins are formed.RESULTS: Two automated methods were employed to rapidly generate anoptimised set of targets, which were subsequently analysed manually. Afinal set of 37 domains or structural repeats, represented 204 times inthe genome, was developed. Using these families enabled us to correlateitems of information from many different resources. Several immediatelyenhance our understanding both of S. coelicolor and also general bacterialmolecular mechanisms, including cell wall biosynthesis regulation andstreptomycete telomere maintenance. DISCUSSION: Delineation of proteindomain families enables detailed analysis of protein function, as well asidentification of likely regions or residues of particular interest. Hencethis kind of prior approach can increase the rate of discovery in thelaboratory. Furthermore we demonstrate that using this type of in silicomethod it is possible to fairly rapidly generate new biologicalinformation from previously uncorrelated data.