Biosynthesis of branched-chain fatty acid in bacilli: FabD (malonyl-CoA:ACP transacylase) is not essential for in vitro biosynthesis of branched-chain fatty acids.
نویسندگان
چکیده
It was found that the partially purified beta-ketoacyl-ACP synthase of Bacillus insolitus did not require the addition of FabD (malonyl-CoA:ACP transacylase, MAT) for the activity assay. This study therefore examined the necessity of FabD protein for in vitro branched-chain fatty acid (BCFA) biosynthesis by crude fatty acid synthetases (FAS) of Bacilli. To discover the involvement of FabD in the BCFA biosynthesis, the protein was removed from the crude FAS by immunoprecipitation. The His-tag fusion protein FabD of Bacillus subtilis was expressed in Escherichia coli and used for the preparation of antibody. The rabbit antibody raised against the expressed fusion protein specifically recognized the FabD in the crude FAS of B. subtilis. Evaluation of the efficacy of the immunoprecipitation showed that a trace of FabD protein was present in the antibody-treated crude FAS. However, this complete removal of FabD from the crude FAS did not abolish its BCFA biosynthesis, but only reduced the level to 50-60% of the control level for acyl-CoA primer and to 80% for alpha-keto-beta-methylvalerate primer. Furthermore, the FabD concentration did not necessarily correlate with the MAT specific activity in the enzyme fractions, suggesting the presence of another enzyme source of MAT activity. This study, therefore, suggests that FabD is not the sole enzyme source of MAT for in vitro BCFA biosynthesis, and implies the existence of a functional connection between fatty acid biosynthesis and another metabolic pathway.
منابع مشابه
Catalysis, specificity, and ACP docking site of Streptomyces coelicolor malonyl-CoA:ACP transacylase.
Malonyl-CoA:ACP transacylase (MAT), the fabD gene product of Streptomyces coelicolor A3(2), participates in both fatty acid and polyketide synthesis pathways, transferring malonyl groups that are used as extender units in chain growth from malonyl-CoA to pathway-specific acyl carrier proteins (ACPs). Here, the 2.0 A structure reveals an invariant arginine bound to an acetate that mimics the mal...
متن کاملXanthomonas campestris FabH is required for branched-chain fatty acid and DSF-family quorum sensing signal biosynthesis
Xanthomonas campestris pv. campestris (Xcc), a Gram-negative phytopathogenic bacterium, causes black rot disease of cruciferous vegetables. Although Xcc has a complex fatty acid profile comprised of straight-chain fatty acids and branched-chain fatty acids (BCFAs), and encodes a complete set of genes required for fatty acid synthesis, there is still little known about the mechanism of BCFA synt...
متن کاملBiosvnthesis of Branched Chain Fattv Acids
Branched chain fatty acids with 15 and 17 carbon atoms occur abundantly in the lipids of Bacillus subtilis (natto) (2), in a species of Sarcina (3), in Micrococcus lysodeikticus (4), and in B. subtilis (ATCC 7059) (1). Recently Horning et al. (5) have presented evidence based on purified enzyme preparation from adipose tissue that branched long chain fatty acids are synthesized by condensation ...
متن کاملIso- and anteiso-fatty acids in bacteria: biosynthesis, function, and taxonomic significance.
Branched-chain fatty acids of the iso and anteiso series occur in many bacteria as the major acyl constituents of membrane lipids. In addition, omega-cyclohexyl and omega-cycloheptyl fatty acids are present in several bacterial species. These two types of fatty acids are synthesized by the repeated condensation of malonyl coenzyme A with one of the branched-chain and cyclic primers by the same ...
متن کاملMutants of Escherichia coli with temperature-sensitive malonyl coenzyme A-acyl carrier protein transacylase.
We have characterized two mutants of Escherichia coli in which fatty acid biosynthesis is adversely affected by elevated temperature. Under conditions which do not alter the activity of wild type cell-free extracts, virtually all of the malonyl coenzyme A-acyl carrier protein (ACP) transacylase and fatty acid synthetase activities present in mutant extracts are thermolabile. Malonyl transacylas...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Bioscience, biotechnology, and biochemistry
دوره 67 10 شماره
صفحات -
تاریخ انتشار 2003