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.
Barden
J A
JA
Department of Anatomy, University of Sydney, NSW, Australia.
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