Activity and anion inhibition studies of the α-carbonic anhydrase from Thiomicrospira crunogena XCL-2 Gammaproteobacterium.

ABSTRACT: Thiomicrospira crunogena XCL-2 expresses an α-carbonic anhydrase (TcruCA). Sequence alignments reveal that TcruCA displays a high sequence identity (>30%) relative to other α-CAs. This includes three conserved histidines that coordinate the active site zinc, a histidine proton shuttling residue, and opposing hydrophilic and hydrophobic sides that line the active site. The catalytic efficiency of TcruCA is considered moderate relative to other α-CAs (k(cat)/K(M)=1.1×10(7) M(-1) s(-1)), being a factor of ten less efficient than the most active α-CAs. TcruCA is also inhibited by anions with Cl(-), Br(-), and I(-), all showing Ki values in the millimolar range (53-361 mM). Hydrogen sulfide (HS(-)) revealed the highest affinity for TcruCA with a Ki of 1.1 μM. It is predicted that inhibition of

SUBMITTER: Mahon BP 

PROVIDER: S-EPMC5358508 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature