title: Substrate-induced conformational changes in sarcoplasmic reticulum Ca2+-ATPase probed by surface modification using diethylpyrocarbonate with mass spectrometry.
abstract: We have identified 15 residues from the surface of sarcoplasmic reticulum Ca(2+)-pump ATPase, by mass spectrometry using diethylpyrocarbonate modification. The reactivity of 9 residues remained high under all the conditions. The reactivity of Lys-515 at the nucleotide site was severely inhibited by ATP, whereas that of Lys-158 in the A-domain decreased by one-half and increased by five-fold in the presence of Ca(2+) and MgF(4), respectively. These are well explained by solvent accessibility, pK(a) and nearby hydrophobicity of the reactive atom on the basis of the atomic structure. However, the reactivity of 4 residues near the interface among A-, N- and P-domain suggested larger conformational changes of these domains in membrane upon binding of Ca(2+) (Lys-436), ATP (Lys-158) and MgF(4) (His-5, -190, Lys-436).
authors: Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.
authors: Ryouhei
authors: R
authors: Narumi
authors: Taibo
authors: T
authors: Yamamoto
authors: Akio
authors: A
authors: Inoue
authors: Toshiaki
authors: T
authors: Arata
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D066298:In Vitro Techniques; D008239:Lysine / Q000737:chemistry; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation / Q000187:drug effects; D017434:Protein Structure, Tertiary; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D013379:Substrate Specificity; D053719:Tandem Mass Spectrometry
chemical_list: D010446:Peptide Fragments; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D008239:Lysine; D004047:Diethyl Pyrocarbonate