X-ray structure of the first `extremo-α-carbonic anhydrase', a dimeric enzyme from the thermophilic bacteriumSulfurihydrogenibium yellowstonenseYO3AOP1

Abstract

SspCA, a novel `extremo-α-carbonic anhydrase' isolated from the thermophilic bacterium Sulfurihydrogenibium yellowstonense YO3AOP1, is an efficient catalyst for the hydration of CO2 and presents exceptional thermostability. Indeed, SspCA retains a high catalytic activity even after being heated to 343-373 K for several hours. Here, the crystallographic structure of this α-carbonic anhydrase (α-CA) is reported and the factors responsible for its function at high temperature are elucidated. In particular, the study suggests that increased structural compactness, together with an increased number of charged residues on the protein surface and a greater number of ionic networks, seem to be the key factors involved in the higher thermostability of this enzyme with respect to its mesophilic homologues. These findings are of extreme importance, since they provide a structural basis for the understanding of the mechanisms responsible for thermal stability in the α-CA family for the first time. The data obtained offer a tool that can be exploited to engineer α-CAs in order to obtain enzymes with enhanced thermostability for use in the harsh conditions of the CO2 capture and sequestration processes.

Cloning, purification and preliminary crystallographic analysis of the complex ofHelicobacter pyloriα-carbonic anhydrase with acetazolamide

“…A sequence-similarity search against proteins with known structure in the RCSB Protein Data Bank revealed that Hp CA shares 39% identity with CA from Sulfurihydrogenibium yellowstonense YO3AOP1 (PDB entry 4g7a; Di Fiore et al, 2013) in a 228-residue overlap and 38% identity with carbonic anhydrase from Neisseria gonorrhoeae (PDB code 1kop; Huang et al, 1998) in a 231-residue overlap. Molecular replacement was performed with Phaser using data to 2.5 Å resolution (McCoy et al, 2005).…”

Sulfonamide inhibition studies of the γ-carbonic anhydrase from the Antarctic bacterium Pseudoalteromonas haloplanktis

“…[4][5][6][7][8][9][10][11]13,[15][16][17][18][19][20][21][22] In fact, all known structural factors and weak interactions involved in protein stability are either reduced in number or modified in psychrophilic enzymes in order to increase their flexibility; but the same structural factors are also implicate for increasing the stability of the thermophilic proteins. [23][24][25][26][27][28][29] Carbonic anhydrases (CAs; EC 4.2.1.1) are metalloenzymes that catalyze CO 2 hydration to bicarbonate and protons. 4,5,[30][31][32][33][34][35][36][37][38] These enzymes are involved in a multitude of physiologic processes in organisms all over the phylogenetic tree, with six genetically distinct CA classes known to date: the a-, b-, c-, d-, f-and g-CAs.…”

Expression and characterization of a recombinant psychrophilicγ-carbonic anhydrase (NcoCA) identified in the genome of the Antarctic cyanobacteria belonging to the genusNostoc

“…Carbon dioxide (CO 2 ) is an important molecule in all life processes and is generated in high amounts in all organisms, which developed catalysts for its transformation into protons and bicarbonates [1][2][3][4][5][6][7][8][9][10][11] . These catalysts are the enzymes known as carbonic anhydrases (CAs, EC 4.2.1.1) which catalyze the CO 2 hydration/dehydration reversible reaction: CO 2 + H 2 O > HCO À 3 + H +1, [3][4][5][6]8,[12][13][14][15][16][17][18][19] .…”