1K54

OXA-10 class D beta-lactamase partially acylated with reacted 6beta-(1-hydroxy-1-methylethyl) penicillanic acid

Summary for 1K54

• Entry DOI: 10.2210/pdb1k54/pdb
• Related: 1K55 1K56 1K57 1e3u 1e4d
• Descriptor: Beta lactamase OXA-10, SULFATE ION, (1R)-2-(1-CARBOXY-2-HYDROXY-2-METHYL-PROPYL)-5,5-DIMETHYL-THIAZOLIDINE-4-CARBOXYLIC ACID, ... (6 entities in total)
• Functional Keywords: beta-lactamase, antibiotic resistance, carbamylation, hydrolase
• Biological source: Pseudomonas aeruginosa; More
• Total number of polymer chains: 4
• Total formula weight: 112743.32

Authors

Golemi, D.,Maveyraud, L.,Vakulenko, S.,Samama, J.P.,Mobashery, S. (deposition date: 2001-10-10, release date: 2001-11-07, Last modification date: 2023-11-15)

Primary citation

Golemi, D.,Maveyraud, L.,Vakulenko, S.,Samama, J.P.,Mobashery, S.
Critical involvement of a carbamylated lysine in catalytic function of class D beta-lactamases.
Proc.Natl.Acad.Sci.USA, 98:14280-14285, 2001

PubMed Abstract: beta-Lactamases are the resistance enzymes for beta-lactam antibiotics, of which four classes are known. beta-lactamases hydrolyze the beta-lactam moieties of these antibiotics, rendering them inactive. It is shown herein that the class D OXA-10 beta-lactamase depends critically on an unusual carbamylated lysine as the basic residue for both the enzyme acylation and deacylation steps of catalysis. The formation of carbamylated lysine is reversible. Evidence is presented that this enzyme is dimeric and carbamylated in living bacteria. High-resolution x-ray structures for the native enzyme were determined at pH values of 6.0, 6.5, 7.5, and 8.5. Two dimers are present per asymmetric unit. One monomer in each dimer was carbamylated at pH 6.0, whereas all four monomers were fully carbamylated at pH 8.5. At the intermediate pH values, one monomer of each dimer was carbamylated, and the other showed a mixture of carbamylated and non-carbamylated lysines. It would appear that, as the pH increased for the sample, additional lysines were "titrated" by carbamylation. A handful of carbamylated lysines are known from protein crystallographic data, all of which have been attributed roles in structural stabilization (mostly as metal ligands) of the proteins. This paper reports a previously unrecognized role for a noncoordinated carbamylate lysine as a basic residue involved in mechanistic reactions of an enzyme, which indicates another means for expansion of the catalytic capabilities of the amino acids in nature beyond the 20 common amino acids in development of biological catalysts.

PubMed: 11724923
DOI: 10.1073/pnas.241442898

Experimental method

X-RAY DIFFRACTION (1.7 Å)