Reference : Beta-lactamase of Bacillus licheniformis 749/C at 2 A resolution.
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
Beta-lactamase of Bacillus licheniformis 749/C at 2 A resolution.
Moews, P. C. [> > > >]
Knox, J. R. [> > > >]
Dideberg, O. [> > > >]
Charlier, Paulette mailto [Université de Liège - ULiège > Département des sciences de la vie > Cristallographie des macromolécules biologiques >]
Frère, Jean-Marie mailto [Université de Liège - ULiège > > Centre d'ingénierie des protéines >]
Wiley Liss, Inc.
Yes (verified by ORBi)
New York
[en] Bacillus/enzymology/genetics ; Bacterial Proteins/genetics/metabolism ; Binding Sites ; Models, Molecular ; Penicillinase/genetics/metabolism ; Penicillins/metabolism ; Protein Binding ; Protein Conformation ; X-Ray Diffraction
[en] 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.

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