title: Cloning, characterization and anion inhibition studies of a γ-carbonic anhydrase from the Antarctic cyanobacterium Nostoc commune.
abstract: We report the cloning and catalytic activity of a γ-carbonic anhydrase (CA, EC 4.2.1.1) isolated from the Antarctic cyanobacterium Nostoc commune, NcoCA. The enzyme has a significant catalytic activity for the physiologic reaction, CO2 hydration to bicarbonate and protons, with a k(cat) of 9.5×10(5) s(-1) and a k(cat)/K(m) of 8.3×10(7) M(-1) × s(-1), being the most catalytically efficient γ-CA investigated so far. An anion inhibition study of NcoCA with inorganic/organic anions is also reported here. Fluoride, sulfate, perchlorate and tetrafluoroborate did not inhibit appreciably NcoCA, whereas the other halides, pseudohalides, bicarbonate, nitrate, nitrite and many complex inorganic anions showed inhibition in the millimolar range. The best NcoCA inhibitors detected so far were diethyldithiocarbamate (K(I) of 0.80 mM) as well as sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid (K(I)s in the range of 70-90 μM). Since γ-CAs are present in carboxysomes, being involved in photosynthesis, this study may be relevant for a better understanding of such processes in some Antarctic organisms.
authors: Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 111, 80131 Napoli, Italy.
authors: Viviana
authors: V
authors: De Luca
authors: Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 111, 80131 Napoli, Italy; Università degli Studi di Firenze, Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche and Laboratorio di Chimica Bioinorganica, Polo Scientifico, Via U. Schiff 6, 50019 Sesto Fiorentino, Florence, Italy.
authors: Sonia
authors: S
authors: Del Prete
authors: Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 111, 80131 Napoli, Italy.
authors: Vincenzo
authors: V
authors: Carginale
authors: Università degli Studi di Firenze, Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche and Laboratorio di Chimica Bioinorganica, Polo Scientifico, Via U. Schiff 6, 50019 Sesto Fiorentino, Florence, Italy.
authors: Daniela
authors: D
authors: Vullo
authors: Università degli Studi di Firenze, Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche and Laboratorio di Chimica Bioinorganica, Polo Scientifico, Via U. Schiff 6, 50019 Sesto Fiorentino, Florence, Italy. Electronic address: claudiu.supuran@unifi.it.
authors: Claudiu T
authors: CT
authors: Supuran
authors: Istituto di Bioscienze e Biorisorse, CNR, Via Pietro Castellino 111, 80131 Napoli, Italy. Electronic address: clemente.capasso@ibbr.cnr.it.
authors: Clemente
authors: C
authors: Capasso
mesh_terms: D000838:Anions / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D055162:Biocatalysis / Q000187:drug effects; D002257:Carbonic Anhydrase Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002256:Carbonic Anhydrases / Q000378:metabolism*; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D015394:Molecular Structure; D050501:Nostoc commune / Q000201:enzymology*; D013329:Structure-Activity Relationship
chemical_list: D000838:Anions; D002257:Carbonic Anhydrase Inhibitors; D002256:Carbonic Anhydrases
keywords: Anions; Antarctic organisms; Carbonic anhydrase; Cyanobacteria; Hydratase activity; Inhibition constant; Metalloenzymes