CONFORMATIONAL RELATIONSHIPS BETWEEN DISTINCT REGIONS IN THE MYOSIN MOLECULE

被引:6
作者
SCHAUB, MC
WATTERSON, JG
LOTH, K
WASER, PG
机构
[1] Institute of Pharmacology, University of Zürich, CH-8006 Zürich
关键词
Allosteric regions; ATP-hydrolysis; Conformational probes; Myosin; Thiol groups;
D O I
10.1016/S0300-9084(79)80273-4
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Up to the present time it has proven difficult to detect conformational changes in the large asymmetrically shaped protein myosin, whether in solution or in its native gel state as it is in the muscle cell. This is even more surprising when one considers that large changes of crossbridge orientation are postulated for the production of force. In this work it is shown that thiol group alkylating reagents are useful tools for probing conformational states, since they are sensitive to even small changes in thiol group reactivity. It is possible to identify the post-hydrolytic intermediate complexes of the Mg-ATPase cycle in myosin, heavy meromyosin and isolated myosin heads. In the long-lived species corresponding to the high fluorescent state, non-essential thiol-3 groups can be selectively blocked. They are located in a region of the molecule where the heads are joined to the rod and since this region is not part of the head, their change in reactivity indicates an allosteric mechanism operative within the myosin heavy chains. Thus they are perhaps well positioned for introducing into myosin labels designed to detect large-scale movement. The use of thiol group probes has also revealed shifts between the post-hydrolytic species in the steady-state Mg-ATPase which result from changing the temperature, changing the ionic strength or blocking the essential thiol-1 groups. These findings are supported by parallel studies on the effects of temperature and pH on the overall turnover rate. It is concluded that the hydrolytic center of myosin can exhibit considerable flexibility in its catalytic function. © 1979 Masson, Paris.
引用
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页码:791 / 801
页数:11
相关论文
共 59 条
[1]   CHARACTERIZATION OF MYOSIN-PRODUCT COMPLEXES AND OF PRODUCT-RELEASE STEPS DURING MAGNESIUM ION-DEPENDENT ADENOSINE-TRIPHOSPHATASE REACTION [J].
BAGSHAW, CR ;
TRENTHAM, DR .
BIOCHEMICAL JOURNAL, 1974, 141 (02) :331-349
[2]  
BIRO NA, 1973, EUR J BIOCHEM, V40, P527
[3]   MYOSIN - SUBUNITS AND THEIR INTERACTIONS [J].
DREIZEN, P ;
GERSHMAN, LC ;
TROTTA, PP ;
STRACHER, A .
JOURNAL OF GENERAL PHYSIOLOGY, 1967, 50 (6P2) :85-&
[4]   RECIPROCAL REACTIVITIES OF SPECIFIC THIOLS WHEN ACTIN BINDS TO MYOSIN [J].
DUKE, J ;
TAKASHI, R ;
UE, K ;
MORALES, MF .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1976, 73 (02) :302-306
[5]  
EISENBERG E, 1978, PROG BIOPHYS MOL BIO, V33, P55
[6]   SHAPE AND FLEXIBILITY OF MYOSIN MOLECULE [J].
ELLIOTT, A ;
OFFER, G .
JOURNAL OF MOLECULAR BIOLOGY, 1978, 123 (04) :505-519
[7]   AMINO-ACID SEQUENCE OF A MYOSIN FRAGMENT THAT CONTAINS SH-1, SH-2, AND NPI-METHYLHISTIDINE [J].
ELZINGA, M ;
COLLINS, JH .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1977, 74 (10) :4281-4284
[8]   ACTIVITY IN RELATION TO PH OF MYOSIN-5'-NUCLEOTIDASE [J].
GILMOUR, D .
NATURE, 1960, 186 (4721) :295-298
[9]  
GORNALL AG, 1949, J BIOL CHEM, V177, P751
[10]   AMINO ACID SEQUENCE AROUND SINGLE 3-METHYLHISTIDINE RESIDUE IN RABBIT SKELETAL MUSCLE MYOSIN [J].
HUSZAR, G ;
ELZINGA, M .
BIOCHEMISTRY, 1971, 10 (02) :229-&