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Structure, activity and thermostability investigations of OXA‐163, OXA‐181 and OXA‐245 using biochemical analysis, crystal structures and differential scanning calorimetry analysis
Author(s) -
Lund Bjarte Aarmo,
Thomassen Ane Molden,
Carlsen Trine Josefine Olsen,
Leiros Hanna-Kirsti S.
Publication year - 2017
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x17013838
Subject(s) - thermostability , differential scanning calorimetry , crystal (programming language) , crystal structure , crystallography , chemistry , klebsiella pneumoniae , escherichia coli , pseudomonas aeruginosa , enzyme , materials science , biology , biochemistry , bacteria , genetics , gene , physics , computer science , programming language , thermodynamics
The first crystal structures of the class D β‐lactamases OXA‐181 and OXA‐245 were determined to 2.05 and 2.20 Å resolution, respectively; in addition, the structure of a new crystal form of OXA‐163 was resolved to 2.07 Å resolution. All of these enzymes are OXA‐48‐like and have been isolated from different clinical Klebsiella pneumoniae strains and also from other human pathogens such as Pseudomonas aeruginosa and Escherichia coli . Here, enzyme kinetics and thermostability studies are presented, and the new crystal structures are used to explain the observed variations. OXA‐245 had the highest melting point ( T m = 55.8°C), as determined by differential scanning calorimetry, compared with OXA‐163 ( T m = 49.4°C) and OXA‐181 ( T m = 52.6°C). The differences could be explained by the loss of two salt bridges in OXA‐163, and an overall decrease in the polarity of the surface of OXA‐181 compared with OXA‐245.