Two Mutations Are Necessary to Convert Class D Beta-lactamase Function to Beta-lactam Sensor Function
Presentation Type
Poster/Portfolio
Presenter Major(s)
Chemistry, Biology
Mentor Information
David Leonard
Department
Chemistry
Location
Henry Hall Atrium 74
Start Date
10-4-2013 10:00 AM
End Date
10-4-2013 11:00 AM
Keywords
Health, Life Science
Abstract
Class D beta-lactamases and beta-lactam sensors share common topological folds and a similar acylation mechanism. The difference between these proteins lie in Class D beta-lactamases' ability to deacylate the substrate, allowing the them to turn over substrate at an astonishing rate. The beta-lactam sensors on the other hand are unable to complete catalysis. Other studies have implicated specific neutral polar residues play a role in the sensors' inability to deacylate bound substrate. With two key active site mutations to Class D beta-lactamase OXA-24, we caused a dramatic drop in ampicillin hydrolysis, suggesting that these two residues alone may be responsible for the functional difference of these two proteins. X-ray crystallographic analysis reveals that an active site water in OXA-24 is missing in the double mutant, providing a possible explanation for the destabilization of the carboxylysine in beta-lactam sensors.
Two Mutations Are Necessary to Convert Class D Beta-lactamase Function to Beta-lactam Sensor Function
Henry Hall Atrium 74
Class D beta-lactamases and beta-lactam sensors share common topological folds and a similar acylation mechanism. The difference between these proteins lie in Class D beta-lactamases' ability to deacylate the substrate, allowing the them to turn over substrate at an astonishing rate. The beta-lactam sensors on the other hand are unable to complete catalysis. Other studies have implicated specific neutral polar residues play a role in the sensors' inability to deacylate bound substrate. With two key active site mutations to Class D beta-lactamase OXA-24, we caused a dramatic drop in ampicillin hydrolysis, suggesting that these two residues alone may be responsible for the functional difference of these two proteins. X-ray crystallographic analysis reveals that an active site water in OXA-24 is missing in the double mutant, providing a possible explanation for the destabilization of the carboxylysine in beta-lactam sensors.