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Mapping nucleotide binding site of calcium ATPase with IR spectroscopy: Effects of ATP γ‐phosphate binding
Author(s) -
Liu Man,
Barth Andreas
Publication year - 2002
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.10113
Subject(s) - chemistry , nucleotide , phosphate , atpase , binding site , imidazole , adenosine triphosphate , atp hydrolysis , crystallography , stereochemistry , biochemistry , enzyme , gene
Abstract The changes in the IR spectra of the sarcoplasmic reticulum Ca 2+ ‐ATPase upon nucleotide binding are recorded in H 2 O at 1°C in different buffers [imidazole, methylimidazole, 3‐( N ‐morpholino)propanesulfonic acid, and phosphate] at different pH values (pH 6.5–7.8). The difference spectra of nucleotide binding are sensitive to the composition of the solvent. With methylimidazole at pH 7.5 providing the largest binding‐induced signals, the effects of γ‐phosphate binding are investigated using ATP, ADP, and β,γ‐iminoadenosine 5′‐triphosphate. The γ‐phosphate contributes ∼20% to the conformational change seen by IR spectroscopy and affects the β‐sheet structures. The IR experiments also reveal the known affinity difference between ADP and ATP. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 267–270, 2002