title: The Structure of the Holo-Acyl Carrier Protein of Leishmania major Displays a Remarkably Different Phosphopantetheinyl Transferase Binding Interface.
abstract: The genome of Leishmania major encodes a type II fatty acid biosynthesis pathway for which no structural or biochemical information exists. Here, for the first time, we have characterized the central player of the pathway, the acyl carrier protein (LmACP), using nuclear magnetic resonance (NMR). Structurally, the LmACP molecule is similar to other type II ACPs, comprising a four-helix bundle, enclosing a hydrophobic core. Dissimilarities in sequence, however, exist in helix II (recognition helix) of the protein. The enzymatic conversion of apo-LmACP into the holo form using type I (Escherichia coli AcpS) and type II (Sfp type) phosphopantetheinyl transferases (PPTs) is relatively slow. Mutagenesis studies underscore the importance of the residues present at the protein-protein interaction interface of LmACP in modulating the activity of PPTs. Interestingly, the cognate PPT for this ACP, the L. major 4'-phosphopantetheinyl transferase (LmPPT), does not show any enzymatic activity toward it, though it readily converts other type I and type II ACPs into their holo forms. NMR chemical shift perturbation studies suggest a moderately tight complex between LmACP and its cognate PPT, suggesting inhibition. We surmise that the unique surface of LmACP might have evolved to complement its cognate enzyme (LmPPT), possibly for the purpose of regulation.
authors: National Institute of Immunology , Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors: Ambrish
authors: A
authors: Kumar
authors: Department of Biochemistry, University of Delhi South Campus , Benito Juarez Road, New Delhi 110 021, India.
authors: Richa
authors: R
authors: Arya
authors: National Institute of Immunology , Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors: Pinakin K
authors: PK
authors: Makwana
authors: National Institute of Immunology , Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors: Rohit Singh
authors: RS
authors: Dangi
authors: National Institute of Immunology , Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors: Usha
authors: U
authors: Yadav
authors: Molecular Biophysics Unit, Indian Institute of Science , Bangalore 560 012, India.
authors: Avadhesha
authors: A
authors: Surolia
authors: Department of Biochemistry, University of Delhi South Campus , Benito Juarez Road, New Delhi 110 021, India.
authors: Suman
authors: S
authors: Kundu
authors: National Institute of Immunology , Aruna Asaf Ali Marg, New Delhi 110 067, India.
authors: Monica
authors: M
authors: Sundd
mesh_terms: D000213:Acyl Carrier Protein / Q000737:chemistry*; D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D020035:Holoenzymes / Q000737:chemistry; D006801:Humans; D018320:Leishmania major / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010963:Plasmodium falciparum / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D015800:Protozoan Proteins / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D017855:Transferases (Other Substituted Phosphate Groups) / Q000737:chemistry*
chemical_list: D000213:Acyl Carrier Protein; D001426:Bacterial Proteins; D020035:Holoenzymes; D015800:Protozoan Proteins; D017855:Transferases (Other Substituted Phosphate Groups); C021364:holo-(acyl-carrier-protein) synthase