title: Identification of a Desaturase Involved in Mycolic Acid Biosynthesis in Mycobacterium smegmatis.
abstract: Mycolic acids are unique long chain fatty acids found in the cell walls of mycobacteria including the tubercle bacillus, Mycobacterium tuberculosis. The introduction of double bonds in mycolic acids remains poorly understood, however, genes encoding two potential aerobic desaturases have been proposed to be involved in this process. Here we show that one of these genes, desA1, is essential for growth of the saprophytic Mycobacterium smegmatis. Depletion of desA1 in a M. smegmatis conditional mutant led to reduction of mycolic acid biosynthesis and loss of viability. The DesA1-depleted cells exhibited two other phenotypes: using 14[C]-labelling, we detected the accumulation of minor mycolic acid-related species that migrated faster in a silver TLC plate. Spiral Time of Flight Mass Spectroscopic analysis suggested the presence of species with sizes corresponding to what were likely monoenoic derivatives of α-mycolic acids. Additionally, conditional depletion led to the presence of free fatty acyl species of lengths ~C26-C48 in the lysing cells. Cell viability could be rescued in the conditional mutant by Mycobacterium tuberculosis desA1, highlighting the potential of desA1 as a new drug target in pathogenic mycobacteria.
authors.affiliation: School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
authors.forename: Albel
authors.initials: A
authors.lastname: Singh
authors.affiliation: School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
authors.forename: Cristian
authors.initials: C
authors.lastname: Varela
authors.affiliation: Heart of England NHS Trust, Birmingham, United Kingdom.
authors.forename: Kiranmai
authors.initials: K
authors.lastname: Bhatt
authors.affiliation: School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
authors.forename: Natacha
authors.initials: N
authors.lastname: Veerapen
authors.affiliation: School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
authors.forename: Oona Y C
authors.initials: OY
authors.lastname: Lee
authors.affiliation: School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
authors.forename: Houdini H T
authors.initials: HH
authors.lastname: Wu
authors.affiliation: School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
authors.forename: Gurdyal S
authors.initials: GS
authors.lastname: Besra
authors.affiliation: School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
authors.forename: David E
authors.initials: DE
authors.lastname: Minnikin
authors.affiliation: Department of Food and Nutrition, Faculty of Contemporary Human Life Science, Tezukayama University, Nara City, Nara, 631-8585, Japan.
authors.forename: Nagatoshi
authors.initials: N
authors.lastname: Fujiwara
authors.affiliation: Advanced and Fundamental Technology Center, JEOL Ltd., Akishima City, Tokyo, 196-8558, Japan.
authors.forename: Kanae
authors.initials: K
authors.lastname: Teramoto
authors.affiliation: School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
authors.forename: Apoorva
authors.initials: A
authors.lastname: Bhatt
mesh_terms: D000081:Acetamides / Q000737:chemistry / Q000494:pharmacology; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002250:Carbon Radioisotopes / Q000737:chemistry; D002855:Chromatography, Thin Layer; D044943:Fatty Acid Desaturases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D020102:Mycobacterium smegmatis / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D009171:Mycolic Acids / Q000032:analysis / Q000378:metabolism*; D016415:Sequence Alignment; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000081:Acetamides; D001426:Bacterial Proteins; D002250:Carbon Radioisotopes; D009171:Mycolic Acids; C030686:acetamide; D044943:Fatty Acid Desaturases