Premium
Major contribution of the type II beta carbonic anhydrase CanB ( C j0237) to the capnophilic growth phenotype of C ampylobacter jejuni
Author(s) -
AlHaideri Halah,
White Michael A.,
Kelly David J.
Publication year - 2016
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.13092
Subject(s) - biology , phenotype , carbonic anhydrase , microbiology and biotechnology , biochemistry , enzyme , gene
Summary C ampylobacter jejuni , the leading cause of human bacterial gastroenteritis, requires low environmental oxygen and high carbon dioxide for optimum growth, but the molecular basis for the carbon dioxide requirement is unclear. One factor may be inefficient conversion of gaseous CO 2 to bicarbonate, the required substrate of various carboxylases. Two putative carbonic anhydrases ( CA s) are encoded in the genome of C . jejuni strain NCTC 11168 ( C j0229 and C j0237). Here, we show that the deletion of the cj0237 ( can B ) gene alone prevents growth in complex media at low (1% v/v) CO 2 and significantly reduces the growth rate at high (5% v/v) CO 2 . In minimal media incubated under high CO 2 , the can B mutant grew on L‐aspartate but not on the key C 3 compounds L‐serine, pyruvate and L‐lactate, showing that CanB is crucial in bicarbonate provision for pyruvate carboxylase‐mediated oxaloacetate synthesis. Nevertheless, purified CanB (a dimeric, anion and acetazolamide sensitive, zinc‐containing type II beta‐class enzyme) hydrates CO 2 actively only above pH 8 and with a high K m (∼34 mM). At typical cytoplasmic pH values and low CO 2 , these kinetic properties might limit intracellular bicarbonate availability. Taken together, our data suggest CanB is a major contributor to the capnophilic growth phenotype of C . jejuni .