2blm
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BETA-LACTAMASE OF BACILLUS LICHENIFORMIS 749(SLASH)C AT 2 ANGSTROMS RESOLUTION
OverviewOverview
Two crystal forms (A and B) of the 29,500 Da Class A beta-lactamase, (penicillinase) from Bacillus licheniformis 749/C have been examined, crystallographically. The structure of B-form crystals has been solved to, 2 A resolution, the starting model for which was a 3.5 A structure, obtained from A-form crystals. The beta-lactamase has an alpha + beta, structure with 11 helices and 5 beta-strands seen also in a penicillin, target DD-peptidase of Streptomyces R61. Atomic parameters of the two, molecules in the asymmetric unit were refined by simulated annealing at, 2.0 A resolution. The R factor is 0.208 for the 27,330 data greater than 3, sigma (F), with water molecules excluded from the model. The catalytic, Ser-70 is at the N-terminus of a helix and is within hydrogen bonding, distance of conserved Lys-73. Also interacting with the Lys-73 are Asn-132, and the conserved Glu-166, which is on a potentially flexible, helix-containing loop. The structure suggests the binding of beta-lactam, substrates is facilitated by interactions with Lys-234, Thr-235, and, Ala-237 in a conserved beta-strand peptide, which is antiparallel to the, beta-lactam's acylamido linkage; an exposed cavity near Asn-170 exists for, acylamido substituents. The reactive double bond of clavulanate-type, inhibitors may interact with Arg-244 on the fourth beta-strand. A very, similar binding site architecture is seen in the DD-peptidase.
About this StructureAbout this Structure
2BLM is a Single protein structure of sequence from Bacillus licheniformis. Active as Beta-lactamase, with EC number 3.5.2.6 Full crystallographic information is available from OCA.
ReferenceReference
Beta-lactamase of Bacillus licheniformis 749/C at 2 A resolution., Moews PC, Knox JR, Dideberg O, Charlier P, Frere JM, Proteins. 1990;7(2):156-71. PMID:2326252
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