title: Head-to-head coiled arrangement of the subunits of the animal fatty acid synthase.
abstract: The role of the beta-ketoacyl synthase domains in dimerization of the 2505 residue subunits of the multifunctional animal FAS has been evaluated by a combination of crosslinking and characterization of several truncated forms of the protein. Polypeptides containing only the N-terminal 971 residues can form dimers, but polypeptides lacking only the N-terminal 422 residue beta-ketoacyl synthase domain cannot. FAS subunits can be crosslinked with spacer lengths as short as 6 A, via cysteine residues engineered near the N terminus of the full-length polypeptides. The proximity of the N-terminal beta-ketoacyl synthase domains and their essential role in dimerization is consistent with a revised model for the FAS in which a head-to-head arrangement of two coiled subunits facilitates functional interactions between the dimeric beta-ketoacyl synthase and the acyl carrier protein domains of either subunit.
authors.affiliation: Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, California 94609, USA.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Witkowski
authors.forename: Alokesh
authors.initials: A
authors.lastname: Ghosal
authors.forename: Anil K
authors.initials: AK
authors.lastname: Joshi
authors.forename: H Ewa
authors.initials: HE
authors.lastname: Witkowska
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Asturias
authors.forename: Stuart
authors.initials: S
authors.lastname: Smith
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D003545:Cysteine / Q000737:chemistry; D019281:Dimerization; D064429:Fatty Acid Synthases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry; D048630:Polyketide Synthases / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D010446:Peptide Fragments; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D048630:Polyketide Synthases; D064429:Fatty Acid Synthases; D003545:Cysteine