title: NMR study of the positions of His-12 and His-119 in the ribonuclease A-uridine vanadate complex.
abstract: The binding of uridine vanadate to ribonuclease A has been investigated by one- and two-dimensional 1H NMR. The homonuclear Nuclear Overhauser and exchange spectroscopy spectrum of the uridine vanadate/RNase A complex exhibits cross peaks between both the C5H and C6H protons of uridine vanadate and the H epsilon 1 proton of His-12 of ribonuclease A. These cross peaks suggest that the H epsilon 1 proton of His-12 is in the vicinity of the uracil base of uridine vanadate, as observed in the crystallographic structure of the uridine vanadate/RNase A complex. However, no cross peaks are observed between the C5H and C6H protons of uridine vanadate and the H epsilon 1 proton of His-119 of ribonuclease A, although they were predicted based upon the distances calculated from coordinates of the crystallographic structure of the complex. These results suggest that there is a significant difference between the positioning of the His-119 side chain in the solution and in the crystallographic structures.
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Ontario, Canada.
authors.forename: T D
authors.initials: TD
authors.lastname: Veenstra
authors.forename: L
authors.initials: L
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D006639:Histidine / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011487:Protein Conformation; D012259:Ribonuclease, Pancreatic / Q000737:chemistry* / Q000378:metabolism; D014529:Uridine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D014638:Vanadates / Q000737:chemistry
chemical_list: C038271:uridine vanadate; D014638:Vanadates; D006639:Histidine; D012259:Ribonuclease, Pancreatic; D014529:Uridine