Taxonomic distribution of proteins containing Lactamase_B domains

The Lactamase_B domain within your query sequence starts at position 168 and ends at position 330, and its E-value is 1.05e-31.

Extracting protein alignment models from the sequence database.

Neuwald AF, Liu JS, Lipman DJ, Lawrence CE
Nucleic Acids Res. 1997; 25: 1665-77

Biologists often gain structural and functional insights into a proteinsequence by constructing a multiple alignment model of the family. Here aprogram called Probe fully automates this process of model constructionstarting from a single sequence. Central to this program is a powerful newmethod to locate and align only those, often subtly, conserved patternsessential to the family as a whole. When applied to randomly chosenproteins, Probe found on average about four times as many relationships asa pairwise search and yielded many new discoveries. These include: anobscure subfamily of globins in the roundworm Caenorhabditis elegans ; twonew superfamilies of metallohydrolases; a lipoyl/biotin swinging armdomain in bacterial membrane fusion proteins; and a DH domain in the yeastBud3 and Fus2 proteins. By identifying distant relationships and mergingfamilies into superfamilies in this way, this analysis further confirmsthe notion that proteins evolved from relatively few ancient sequences.Moreover, this method automatically generates models of these ancientconserved regions for rapid and sensitive screening of sequences.

The 3-D structure of a zinc metallo-beta-lactamase from Bacillus cereusreveals a new type of protein fold.

Carfi A, Pares S, Duee E, Galleni M, Duez C, Frere JM, Dideberg O
EMBO J. 1995; 14: 4914-21

The 3-D structure of Bacillus cereus (569/H/9) beta-lactamase (EC3.5.2.6), which catalyses the hydrolysis of nearly all beta-lactams, hasbeen solved at 2.5 A resolution by the multiple isomorphous replacementmethod, with density modification and phase combination, from crystals ofthe native protein and of a specially designed mutant (T97C). The currentmodel includes 212 of the 227 amino acid residues, the zinc ion and 10water molecules. The protein is folded into a beta beta sandwich withhelices on each external face. To our knowledge, this fold has never beenobserved. An approximate internal molecular symmetry is found, with a2-fold axis passing roughly through the zinc ion and suggesting a possiblegene duplication. The active site is located at one edge of the beta betasandwich and near the N-terminal end of a helix. The zinc ion iscoordinated by three histidine residues (86, 88 and 149) and a watermolecule. A sequence comparison of the relevant metallo-beta-lactamases,based on this protein structure, highlights a few well-conserved aminoacid residues. The structure shows that most of these residues are in theactive site. Among these, aspartic acid 90 and histidine 210 participatein a proposed catalytic mechanism for beta-lactam hydrolysis.