Sandbox Reserved 994: Difference between revisions

OXA-24 is a monomeric protein. The active site is composed of a short <nowiki>310</nowiki> helix and a β-sheet. The active site of OXA-24 is characterized by a hydrophobic pocket, which is representative of Class D β-lactamases as a whole. The hydrophobic bridge contributes to the substrate specificity for carbapenems and is composed of an arrangement of the Tyr-112 and Met-223 side chains. These residues block the active site and only allow a very specific binding configuration of antibiotics. The active site is overall positively charged and contains a sulfate ion along with other solvent molecules when no substrate is bound. The mechanism of attack is through the use of three catalytic residues: Serine-81, Carboxylated Lysine-84, and Serine-128. The hydroxyl chain of Ser-128 conforms in the direction of the active-serine Ser-81, and contributes to the catalytic mechanism.<ref>doi:10.1073/pnas.0607557104</ref>