Flexibility of the myosin heavy chain: direct evidence that the region containing SH1 and SH2 can move 10 .ANG. under the influence of nucleotide binding

Huston, Edward E.; Grammer, Jean C.; Yount, Ralph G.

doi:10.1021/bi00425a011

Cited by 70 publications

(54 citation statements)

References 52 publications

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“…It is expected that any other residue in this latter location would alter the conformation of this segment and change the domain-domain interactions. Chemical and structural studies of myosin have indicated that there must be a significant structural rearrangement associated with the reactive sulffihydryl groups during the contractile cycle (38)(39)(40)(41). In the structure of chicken skeletal myosin Si, these two residues are separated by an a-helix where their side chains point in opposite directions (23), yet they can be cross-linked in the presence of nucleotide (42)(43)(44) and chemical modification of the cysteines changes the kinetic properties of myosin (45,46).…”

Section: Resultsmentioning

confidence: 99%

Structural interpretation of the mutations in the beta-cardiac myosin that have been implicated in familial hypertrophic cardiomyopathy.

Rayment

Holden

Sellers

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

212

142

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In 10-30% of hypertrophic cardiomyopathy kindreds, the disease is caused by >29 missense mutations in the cardiac f8-myosin heavy chain (AYIH7) gene. The amino acid sequence similarity between chicken skeletal muscle and human a-cardiac myosin and the three-dimensional structure of the chicken skeletal muscle myosin head have provided the opportunity to examine the structural consequences of these naturally occurring mutations in human ,8-cardiac myosin. This study demonstrates that the mutations are related to distinct structural and functional domains. Twenty-four are clustered around four specific locations in the myosin head that are (i) associated with the actin binding interface, (ii) around the nucleotide binding site, (iii) adjacent to the region that connects the two reactive cysteine residues, and (iv) in close proximity to the interface of the heavy chain with the essential light chain. The remaining five mutations are in the myosin rod. The locations of these mutations provide insight into the way they impair the functioning of this molecular motor and also into the mechanism of energy transduction.

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Section: Resultsmentioning

confidence: 99%

Structural interpretation of the mutations in the beta-cardiac myosin that have been implicated in familial hypertrophic cardiomyopathy.

Rayment

Holden

Sellers

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

212

142

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“…Under appropriate conditions, differences in reactivity can be used to characterize the environments of such sidechain groups. Kaplan presumably, be considered zero-length cross-links (134,135). Such linkages appear to be formed only when the reacting groups are in close proximity.…”

Section: Side-chain Reactivitiesmentioning

confidence: 99%

Chemical modifications of proteins: history and applications

Means¹,

Feeney²

1990

Bioconjugate Chem.

183

170

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With roots in ancient formulations, methods for the chemical derivatization of proteins continue to expand and develop. The creation of this new journal dealing exclusively with bioconjugate chemistry was barely conceivable just a few years ago. An explosion of interest in the subject during the last decade is, however, easily seen. The tremendous growth in both the number of publications and in the number of research groups involved in these kinds of studies has been promoted by both practical interests related, for example, in some cases to possible pharmacological or medical diagnostic applications and by interest in questions of fundamental biochemical structure and function.Greatly Reagents have been designed to preserve electrostatic charge (4,5), to alter electrostatic charge (6), and to increase hydrophobicity (7,8). Reagents and procedures have been developed to decrease immunogenicity (9, 20), to increase and decrease susceptibility to proteolysis (22-23), to increase UV or visible absorbancy (14), to introduce fluorescent labels (25,16), spin labels (27), radiolabels , various metal ions (22), magnetic microspheres (22,23), and electron-dense substituents (24), to increase the content of certain low-abundance nonradioactive isotopes (25)

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“…The crystal structure of chicken pectoralis muscle S1 displays these cysteines in a bent ␣-helix, separated from one another by 18 Å and facing opposite sides of the molecule (2). However, crosslinking experiments using rabbit skeletal muscle myosin demonstrate that during the stroking cycle, the two approach more closely than in the absence of nucleotide (10) and can be directly joined by a disulfide linkage, indicative of a separation of only about 3 Å and a substantially altered geometry (11). The conformational changes are not purely local, in that either cysteine can cross-link with residues in other parts of the structure (for example, SH1-Cys 522 , and SH2-Cys 540 in rabbit (12,13)) during the cycle.…”

mentioning

confidence: 99%

Cold-sensitive Mutants G680V and G691C ofDictyostelium Myosin II Confer Dramatically Different Biochemical Defects

Patterson

Ruppel

et al. 1997

Journal of Biological Chemistry

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Cold-sensitive myosin mutants represent powerful tools for dissecting discrete deficiencies in myosin function. Biochemical characterization of two such mutants, G680V and G691C, has allowed us to identify separate facets of myosin motor function perturbed by each alteration. Compared with wild type, the G680V myosin exhibits a substantially enhanced affinity for several nucleotides, decreased ATPase activity, and overoccupancy or creation of a novel strongly actin-binding state. The properties of the novel strong binding state are consistent with a partial arrest or pausing at the onset of the mechanical stroke. The G691C mutant, on the other hand, exhibits an elevated basal ATPase indicative of premature phosphate release. By releasing phosphate without a requirement for actin binding, the G691C can bypass the part of the cycle involving the mechanical stroke. The two mutants, despite having alterations in glycine residues separated by only 11 residues, have dramatically different consequences on the mechanochemical cycle.The study of the family of molecular motors recently has been invigorated by the availability of crystal structures of both the myosin (1-5) and kinesin family members (6, 7). This information, combined with a wealth of biochemical characterization of these motors, provides a platform on which to build a complete understanding of the mechanics of these pivotal cellular components. In a complementary approach, we have been generating conditionally functional (cold-sensitive) mutants of myosin II in the Dictyostelium system (8, 9). In our isolation of cold-sensitive myosin mutants, we uncovered two mutations in a biochemically renowned region of the protein, a helical element that houses two highly reactive cysteines in rabbit myosin.This region of myosin was first characterized because of the chemical accessibility of two cysteines contained within it (positions 697 (SH2) and 707 (SH1) in rabbit myosin). The crystal structure of chicken pectoralis muscle S1 displays these cysteines in a bent ␣-helix, separated from one another by 18 Å and facing opposite sides of the molecule (2). However, crosslinking experiments using rabbit skeletal muscle myosin demonstrate that during the stroking cycle, the two approach more closely than in the absence of nucleotide (10) and can be directly joined by a disulfide linkage, indicative of a separation of only about 3 Å and a substantially altered geometry (11). The conformational changes are not purely local, in that either cysteine can cross-link with residues in other parts of the structure (for example, SH1-Cys 522 , and SH2-Cys 540 in rabbit (12, 13)) during the cycle. Chemical modification studies have demonstrated that addition of bulky hydrophobic groups to the cysteines dramatically changes the properties of the myosin molecule, particularly with regard to the promiscuity and activity of its ATPase. The physiological substrate of myosin is Mg 2ϩ -ATP which supports only low-level ATPase activity in the absence of actin. However, if provided with Ca 2...

show abstract

Flexibility of the myosin heavy chain: direct evidence that the region containing SH1 and SH2 can move 10 .ANG. under the influence of nucleotide binding

Cited by 70 publications

References 52 publications

Structural interpretation of the mutations in the beta-cardiac myosin that have been implicated in familial hypertrophic cardiomyopathy.

Structural interpretation of the mutations in the beta-cardiac myosin that have been implicated in familial hypertrophic cardiomyopathy.

Chemical modifications of proteins: history and applications

Cold-sensitive Mutants G680V and G691C ofDictyostelium Myosin II Confer Dramatically Different Biochemical Defects

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