TY - JOUR
T1 - Effect of complexes of ADP and phosphate analogs on the conformation of the Cys707-Cys697 region of myosin subfragment 1
AU - Phan, B. C.
AU - Peyser, Y. M.
AU - Reisler, E.
AU - Muhlrad, A.
PY - 1997
Y1 - 1997
N2 - Recent crystallographic studies have suggested structural differences between the complexes of S1 · Mg ADP with the phosphate analogs aluminium fluoride (AlF4-), vanadate (VO43-) and beryllium fluoride (BeF(x)) [Fisher, A. J., Smith, C. A., Thoden, J. B., Smith, R., Sutoh, K., Holden, H. M. and Rayment, I. (1995) Biochemistry 34, 8960-8972; Smith, R. and Rayment, I. (1996) Biochemistry 35, 5404-5417]. In this work, chemical modifications, namely labeling of Cys707 (the reactive SH1 thiol) and Cys707-Cys697 (SH1-SH2) cross-linking, were used to compare the S1 · ADP BeF(x), S1 · ADP AlF4- and S1 · ADP · VO43- complexes with specific states of the myosin-ATPase pathway. Modification of Cys707 with the fluorescent monofunctional reagents 7-diethylamino-3-(4'-maleimidylphenyl)-4-methylcoumarin and N-iodoacetyl-N'-(5-sulfo-1-naphtyl)ethylenediamine has shown that the reactivity of the SH1 group depends on the nucleotide bound to S1. The observed rates of Cys707 modification at 20°C lead to the conclusion that S1 · ADP BeF(x) is similar to S1* · ATP, while S1 · ADP · AlF4- and S1 · ADP · VO43- are more similar to S1** · ADP · P(i). The conformations of the analog states were also compared by monitoring the dissociation of the fluorescent nucleotide analog 1-N6'-ethenoadenosine diphosphate (ADP[C2H2]]) from the active site of Cys707-modified (by N-ethylmaleimide) and Cys707-Cys697 cross-linked (by N,N'-p-phenylene dimaleimide) S1 · ADP[C2H2] · AlF4- and S1 · ADP[C2H2] · BeF(x). Our results suggest that the conformations of the S1 · ADP AlF4-, S1 · ADP · VO43- and S1 · ADP · BeF(x) complexes in the Cys707-Cys697 region are distinct from each other, with the former two at least partially resembling the S1** ADP · P(i) state, while the latter is similar to the prehydrolyzed S1* · ATP state.
AB - Recent crystallographic studies have suggested structural differences between the complexes of S1 · Mg ADP with the phosphate analogs aluminium fluoride (AlF4-), vanadate (VO43-) and beryllium fluoride (BeF(x)) [Fisher, A. J., Smith, C. A., Thoden, J. B., Smith, R., Sutoh, K., Holden, H. M. and Rayment, I. (1995) Biochemistry 34, 8960-8972; Smith, R. and Rayment, I. (1996) Biochemistry 35, 5404-5417]. In this work, chemical modifications, namely labeling of Cys707 (the reactive SH1 thiol) and Cys707-Cys697 (SH1-SH2) cross-linking, were used to compare the S1 · ADP BeF(x), S1 · ADP AlF4- and S1 · ADP · VO43- complexes with specific states of the myosin-ATPase pathway. Modification of Cys707 with the fluorescent monofunctional reagents 7-diethylamino-3-(4'-maleimidylphenyl)-4-methylcoumarin and N-iodoacetyl-N'-(5-sulfo-1-naphtyl)ethylenediamine has shown that the reactivity of the SH1 group depends on the nucleotide bound to S1. The observed rates of Cys707 modification at 20°C lead to the conclusion that S1 · ADP BeF(x) is similar to S1* · ATP, while S1 · ADP · AlF4- and S1 · ADP · VO43- are more similar to S1** · ADP · P(i). The conformations of the analog states were also compared by monitoring the dissociation of the fluorescent nucleotide analog 1-N6'-ethenoadenosine diphosphate (ADP[C2H2]]) from the active site of Cys707-modified (by N-ethylmaleimide) and Cys707-Cys697 cross-linked (by N,N'-p-phenylene dimaleimide) S1 · ADP[C2H2] · AlF4- and S1 · ADP[C2H2] · BeF(x). Our results suggest that the conformations of the S1 · ADP AlF4-, S1 · ADP · VO43- and S1 · ADP · BeF(x) complexes in the Cys707-Cys697 region are distinct from each other, with the former two at least partially resembling the S1** ADP · P(i) state, while the latter is similar to the prehydrolyzed S1* · ATP state.
KW - Chemical modification
KW - Myosin
KW - Phosphate analog
KW - Subfragment 1
KW - Thiol group
UR - http://www.scopus.com/inward/record.url?scp=0031032881&partnerID=8YFLogxK
U2 - 10.1111/j.1432-1033.1997.00636.x
DO - 10.1111/j.1432-1033.1997.00636.x
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
C2 - 9057826
AN - SCOPUS:0031032881
SN - 0014-2956
VL - 243
SP - 636
EP - 642
JO - European Journal of Biochemistry
JF - European Journal of Biochemistry
IS - 3
ER -