Conformation of the ATP binding peptide in actin revealed by proton NMR spectroscopy.
The actin peptide 106-124 exists in a completely conserved region of the sequence and binds strongly to both ATP and tripolyphosphate. Binding particularly affects residues 116 and 118 and generally affects the two segments 115-118 and 121-124 [Barden, J. A., & Kemp, B. E. (1987) Biochemistry 26, 1471-1478]. One-dimensional nuclear Overhauser enhancement difference spectroscopy was used to detect molecular interactions between both adjacent and nonadjacent residues. The N-terminal segment 106-112 was found to be largely extended. A sharp bend was detected between Pro-112 and Lys-113. The triphosphate moiety binds to the strongly hydrophilic central segment of the peptide. Evidence was obtained for a reverse turn involving residues 121-124. Amide proton temperature coefficients and coupling constants provide evidence for a type I beta-turn. A model of the ATP binding site is proposed together with its relationship to other parts of the actin structure and to the phalloidin binding site.
Department of Anatomy, University of Sydney, NSW, Australia.
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JA
Barden
D000199:Actins / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D019791:Guanidine; D006146:Guanidines / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D010446:Peptide Fragments / Q000378:metabolism*; D010455:Peptides / Q000138:chemical synthesis; D011487:Protein Conformation
D000199:Actins; D006146:Guanidines; D010446:Peptide Fragments; D010455:Peptides; C033025:actin subfragments; D000255:Adenosine Triphosphate; D019791:Guanidine