A Biotin Biosynthesis Gene Restricted to Helicobacter.

Area of Science:

• Microbiology
• Biochemistry
• Enzymology

Background:

• Biotin synthesis in bacteria typically involves cleaving pimeloyl-acyl carrier protein (ACP) methyl ester.
• The enzyme BioH in Escherichia coli is the known enzyme for this cleavage, working with BioC.
• Genome analyses reveal that many bacteria with bioC lack bioH, suggesting alternative enzymes exist.

Purpose of the Study:

• To identify the enzyme responsible for pimeloyl-ACP methyl ester cleavage in Helicobacter pylori.
• To characterize the function and mechanism of this novel enzyme.
• To explore its potential as a drug target for Helicobacter infections.

Main Methods:

• Complementation of an E. coli bioH deletion strain to isolate the H. pylori gene.
• Purification of the identified enzyme, BioV.
• In vitro assays using pimeloyl-ACP methyl ester as substrate.
• Reconstitution of an in vitro desthiobiotin synthesis system to confirm BioV's role.

Main Results:

• The H. pylori gene bioV was isolated and shown to encode an enzyme that cleaves pimeloyl-ACP methyl ester to pimeloyl-ACP.
• Purified BioV utilizes a catalytic triad essential for its esterase activity.
• BioV was demonstrated to be crucial for biotin biosynthesis in H. pylori.

Conclusions:

• Helicobacter pylori employs a novel enzyme, BioV, for biotin biosynthesis, distinct from the canonical BioH pathway.
• BioV homologues are specific to H. pylori and related species, making them potential targets for selective drug development against these infections.