The γ-carbonic anhydrase from the pathogenic bacterium Vibrio cholerae is potently activated by amines and amino acids

ABSTRACT ChiA, an 88-kDa endochitinase encoded by the chiA gene of the gram-negative enteropathogen Vibrio cholerae, is secreted via the eps-encoded main terminal branch of the general secretory pathway (GSP), a mechanism which also transports cholera toxin. To localize the extracellular transport signal of ChiA that initiates transport of the protein through the GSP, a chimera comprised of ChiA fused at the N terminus with the maltose-binding protein (MalE) of Escherichia coli and fused at the C terminus with a 13-amino-acid epitope tag (E-tag) was expressed in strain 569B(chiA::Kanr), a chiA-deficient but secretion-competent mutant of V. cholerae. Fractionation studies revealed that blockage of the natural N terminus and C terminus of ChiA did not prevent secretion of the MalE-ChiA-E-tag chimera. To locate the amino acid sequences which encoded the transport signal, a series of truncations of ChiA were engineered. Secretion of the mutant polypeptides was curtailed only when ChiA was deleted from the N terminus beyond amino acid position 75 or from the C terminus beyond amino acid 555. A mutant ChiA comprised of only those amino acids was secreted by wild-type V. cholerae but not by an epsD mutant, establishing that amino acids 75 to 555 independently harbored sufficient structural information to promote secretion by the GSP of V. cholerae. Cys77 and Cys537, two cysteines located just within the termini of ChiA(75-555), were not required for secretion, indicating that those residues were not essential for maintaining the functional activity of the ChiA extracellular transport signal.

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Carbonic anhydrase activators: Activation of the human isoforms VII (cytosolic) and XIV (transmembrane) with amino acids and amines

Bioorganic & Medicinal Chemistry Letters ◽

10.1016/j.bmcl.2007.05.052 ◽

2007 ◽

Vol 17 (15) ◽

pp. 4107-4112 ◽

Cited By ~ 33

Author(s):

Daniela Vullo ◽

Alessio Innocenti ◽

Isao Nishimori ◽

Andrea Scozzafava ◽

Kai Kaila ◽

...

Keyword(s):

Amino Acids ◽

Carbonic Anhydrase ◽

Human Isoforms

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The El Tor Biotype of Vibrio cholerae Exhibits a Growth Advantage in the Stationary Phase in Mixed Cultures with the Classical Biotype

Journal of Bacteriology ◽

10.1128/jb.01180-09 ◽

2009 ◽

Vol 192 (4) ◽

pp. 955-963 ◽

Cited By ~ 18

Author(s):

Subhra Pradhan ◽

Amit K. Baidya ◽

Amalendu Ghosh ◽

Kalidas Paul ◽

Rukhsana Chowdhury

Keyword(s):

Amino Acids ◽

Stationary Phase ◽

Vibrio Cholerae ◽

Competitive Growth ◽

Small Peptides ◽

Ileal Loop ◽

Infant Mouse ◽

Culture Filtrates ◽

El Tor

ABSTRACT Vibrio cholerae strains of the O1 serogroup that typically cause epidemic cholera can be classified into two biotypes, classical and El Tor. The El Tor biotype emerged in 1961 and subsequently displaced the classical biotype as a cause of cholera throughout the world. In this study we demonstrate that when strains of the El Tor and classical biotypes were cocultured in standard LB medium, the El Tor strains clearly had a competitive growth advantage over the classical biotype starting from the late stationary phase and could eventually take over the population. The classical biotype produces extracellular protease(s) in the stationary phase, and the amounts of amino acids and small peptides in the late stationary and death phase culture filtrates of the classical biotype were higher than those in the corresponding culture filtrates of the El Tor biotype. The El Tor biotype cells could utilize the amino acids more efficiently than the classical biotype under the alkaline pH of the stationary phase cultures but not in medium buffered to neutral pH. The growth advantage of the El Tor biotype was also observed in vivo using the ligated rabbit ileal loop and infant mouse animal models.

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