Title

The largest open reading frame (pks12) in the Mycobacterium tuberculosis genome is involved in pathogenesis and dimycocerosyl phthiocerol synthesis

Authors

Authors

T. D. Sirakova; V. S. Dubey; H. J. Kim; M. H. Cynamon;P. E. Kolattukudy

Abbreviated Journal Title

Infect. Immun.

Keywords

MYCOCEROSIC ACID SYNTHASE; MODULAR POLYKETIDE SYNTHESES; BACILLUS-CALMETTE-GUERIN; BOVIS BCG; GENE-CLUSTER; ACYL-COA; BIOSYNTHESIS; SEQUENCE; ENVELOPE; DOMAINS; Immunology; Infectious Diseases

Abstract

The cell wall lipids in Mycobacterium tuberculosis are probably involved in pathogenesis. The largest open reading frame in the genome of M. tuberculosis H37Rv, pks12, is unique in that it encodes two sets of domains needed to produce fatty acids. Apks12-disrupted mutant was produced, and disruption was confirmed by both PCR analysis and Southern blotting. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that a 430-kDa protein band present in the wild type was missing in the mutant. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MS) and liquid chromatography (LC)-MS analysis of tryptic peptides showed that 54 peptides distributed throughout this protein matched the pks12-encoded sequence. Biochemical analysis using [1-C-14] propionate as the radiotracer showed that the pks12 mutant was deficient in the synthesis of dimycocerosyl phthiocerol (DIM). SDS-PAGE, immunoblot analysis of proteins, and analysis of fatty acids showed that the mutant can produce mycocerosic acids. Thus, the pks12 gene is probably involved in the synthesis of phthiocerol, the dioll required for DIM synthesis. Growth of the pks12 mutant was attenuated in mouse alveolar macrophage cell line MH-S, and the virulence of the mutant in vivo was highly attenuated in a murine model. Thus, pks12 probably participates in DIM production and its expression is involved in pathogenesis.

Journal Title

Infection and Immunity

Volume

71

Issue/Number

7

Publication Date

1-1-2003

Document Type

Article

Language

English

First Page

3794

Last Page

3801

WOS Identifier

WOS:000183797200016

ISSN

0019-9567

Share

COinS