Investigating protein structural plasticity by surveying the consequence of an amino acid deletion from TEM-1 beta-lactamase.
While the deletion of an amino acid is a common mutation observed in nature, it is generally thought to be disruptive to protein structure. Using a directed evolution approach, we find that the enzyme TEM-1 beta-lactamase was broadly tolerant to the deletion mutations sampled. Circa 73% of the variants analysed retained activity towards ampicillin, with deletion mutations observed in helices and strands as well as regions important for structure and function. Several deletion variants had enhanced activity towards ceftazidime compared to the wild-type TEM-1 demonstrating that removal of an amino acid can have a beneficial outcome.
School of Biosciences, Biomedical Sciences Building, Museum Avenue, Cardiff University, Cardiff CF10 3US, UK.
Alan M
AM
Simm
Amy J
AJ
Baldwin
Kathy
K
Busse
D Dafydd
DD
Jones
D000595:Amino Acid Sequence / Q000235:genetics*; D000667:Ampicillin / Q000737:chemistry*; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002442:Ceftazidime / Q000737:chemistry*; D019143:Evolution, Molecular; D017433:Protein Structure, Secondary / Q000235:genetics; D017384:Sequence Deletion; D013329:Structure-Activity Relationship; D013379:Substrate Specificity / Q000235:genetics; D001618:beta-Lactamases / Q000737:chemistry / Q000235:genetics*
D000900:Anti-Bacterial Agents; D000667:Ampicillin; D002442:Ceftazidime; D001618:beta-Lactamases; C034413:beta-lactamase TEM-1