Structure of the myosin head in solution and the effect of light chain 2 removal

Garrigos, Manuel; Mallam, Simon; Vachette, Patrice; Bordas, J.

doi:10.1016/s0006-3495(92)81743-5

Cited by 6 publications

(12 citation statements)

References 36 publications

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“…Here we have analyzed the Rg over the same 52 range as that employed by Wakabayashi et al (1992) (s2 = 0.778-2.22 X 10-3 nm-2). As will be discussed later, this range, and to a lesser extent the somewhat lower range of S2 employed by Garrigos et al (1992), yielded an Reff(0) that is somewhat smaller than the in vacuo Rg calculated from the S1 structure (Rayment et al, 1993a). Nevertheless, the range used by Wakabayashi et al (1992) has been employed in this v work because it minimizes the effect of any residual aggregation and minimizes concentration dependence due to excluded volume effects; it also allows direct comparison with their results.…”

Section: The Rg Of Simentioning

confidence: 88%

“…Such effects might be expected inasmuch as there have been reports (Vibert and Cohen, 1988; Rayment et al, 1993b) of possible flexibility in the light-chain binding region of S1, which consists of a long, single a-helix surrounded by the two light chains. There have been small but potentially important differences between the Rg values reported by different laboratories (Mendelson et al, 1991;Garrigos et al, 1992;Wakabayashi et al, 1992), which need to be explored before such a comparison can be meaningfully undertaken.…”

Section: Introductionmentioning

confidence: 99%

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The radius of gyration of native and reductively methylated myosin subfragment-1 from neutron scattering

Stone

Schneider

Huang

et al. 1995

Biophysical Journal

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Reductive methylation of nearly all lysine groups of myosin subfragment-1 (S1) was required for crystallization and solution of its structure at atomic resolution. Possible effects of such methylation on the radius of gyration of chicken skeletal muscle myosin S1 have been investigated by using small-angle neutron scattering. In addition, we have investigated the effect of MgADP.Vi, which is thought to produce an analog of the S1.ADP.Pi state, on the S1 radius of gyration. We find that although methylation of S1, with or without SO42- ion addition, does not significantly alter the structure, addition of ADP plus vanadate does decrease the radius of gyration significantly. The S1 crystal structure predicts a radius of gyration close to that measured here by neutron scattering. These results suggest that the overall shape by crystallography resembles nucleotide-free S1 in solution. In order to estimate the effect of residues missing from the crystal structure, the structure of missing loops was estimated by secondary-structure prediction methods. Calculations using the complete crystal structure show that a simple closure of the nucleotide cleft by a rigid-body torsional rotation of residues (172-180 to 670) around an axis running along the base of the cleft alone does not produce changes as large as seen here and in x-ray scattering results. On the other hand, a rigid body rotation of either the light-chain binding domain (767 to 843 plus light chains) or of a portion of 20-kDa peptide plus this domain (706 to 843 plus light chains) is more readily capable of producing such changes.

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Section: The Rg Of Simentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

The radius of gyration of native and reductively methylated myosin subfragment-1 from neutron scattering

Stone

Schneider

Huang

et al. 1995

Biophysical Journal

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“…This could be achieved either by having the free portion of S2 much shorter than its full length (Bagni et al, 1990) or by having S2 attach to myosin in such a way that the projection of S2 into a plane containing actin and myosin filaments was much shorter than its true length. Indeed, such an angled attachment of Si seems a requirement of the cross-bridge model, because most recent descriptions of the dimension and attachment of the S1 head show its length to be 16-19 nm (Garrigos et al, 1992;Rayment et al, 1993), whereas the space between the surface of the actin and myosin filaments is only 12 nm at slack length. It should be noted that use of NaCl to vary saline tonicity and, hence, lattice spacing causes a sarcoplasmic ionic strength change that may also affect the magnitude of the radial force.…”

Section: Discussionmentioning

confidence: 99%

Lattice spacing changes accompanying isometric tension development in intact single muscle fibers

Bagni

Cecchi

Griffiths

et al. 1994

Biophysical Journal

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The myosin lattice spacing of single intact muscle fibers of the frog, Rana temporaria, was studied in Ringer's solution (standard osmolarity 230 mOsm) and hyper- and hypotonic salines (1.4 and 0.8 times standard osmolarity respectively) in the relaxed state, during "fixed end" tetani, and during shortening, using synchrotron radiation. At standard tonicity, a tetanus was associated with an initial brief lattice expansion (and a small amount of sarcomere shortening), followed by a slow compression (unaccompanied by sarcomere length changes). In hypertonic saline (myosin lattice compressed by 8.1%), these spacing changes were suppressed, in hypotonic saline (lattice spacing increased by 7.5%), they were enhanced. During unloaded shortening of activated fibers, a rapid lattice expansion occurred at all tonicities, but became larger as tonicity was reduced. This expansion was caused in part by the change in length of the preparation, but also by a recoil of a stressed radial compliance associated with axial force. The lattice spacing during unloaded shortening was equal to or occasionally greater than predicted for a relaxed fiber at that sarcomere length, indicating that the lattice compression associated with activation is rapidly reversed upon loss of axial force. Lattice recompression occurred upon termination of shortening under standard and hypotonic conditions, but was almost absent under hypertonic conditions. These observations indicate that axial cross-bridge tension is associated with a compressive radial force in intact muscle fibers at full overlap; however, this radial force exhibits a much greater sensitivity to lattice spacing than does the axial force.

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“…(i) The myosin heads have an elongated and slightly curved shape, with a maximal width of ca 6.0 nm and a maximal length of 17.0-18.0 nm (Garrigos et al, 1992;Wakabayashi et al, 1992;Rayment et al, 1993a). Figure 21 illustrates the behaviour of the F~ for objects of such dimensions.…”

Section: Myosin-based Meridional Reflectionsmentioning

confidence: 99%

Time-resolved X-ray diffraction studies of myosin head movements in live frog sartorius muscle during isometric and isotonic contractions

Martin-Fernandez

Bordas

Diakun

et al. 1994

J Muscle Res Cell Motil

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Using the facilities at the Daresbury Synchrotron Radiation Source, meridional diffraction patterns of muscles at ca 8 degrees C were recorded with a time resolution of 2 or 4 ms. In isometric contractions tetanic peak tension (P0) is reached in ca 400 ms. Under such conditions, following stimulation from rest, the timing of changes in the major reflections (the 38.2 nm troponin reflection, and the 21.5 and 14.34/14.58 nm myosin reflections) can be explained in terms of four types of time courses: K1, K2, K3 and K4. The onset of K1 occurs immediately after stimulation, but that of K2, K3 and K4 is delayed by a latent period of ca 16 ms. Relative to the end of their own latent periods the half-times for K1, K2, K3 and K4 are 14-16, 16, 32 and 52 ms, respectively. In half-times, K1, K2, K3 lead tension rise by 52, 36 and 20 ms, respectively. K4 parallels the time course of tension rise. From an analysis of the data we conclude that K1 reflects thin filament activation which involves the troponin system; K2 arises from an order-disorder transition during which the register between the filaments is lost; K3 is due to the formation of an acto-myosin complex which (at P0) causes 70% or more of the heads to diffract with actin-based periodicities; and K4 is caused by a change in the axial orientation of the myosin heads (relative to thin filament axis) which is estimated to be from 65-70 degrees at rest to ca 90 degrees at P0. Isotonic contraction experiments showed that during shortening under a load of ca 0.27 P0, at least 85% of the heads (relative to those forming an acto-myosin complex at P0) diffract with actin-based periodicities, whilst their axial orientation does not change from that at rest. During shortening under a negligible load, at most 5-10% of the heads (relative to those forming an acto-myosin complex at P0) diffract with actin-based periodicities, and their axial orientation also remains the same as that at rest. This suggests that in isometric contractions the change in axial orientation is not the cause of active tension production, but rather the result of it. Analysis of the data reveals that independent of load, the extent of asynchronous axial motions executed by most of the cycling heads is no more than 0.5-0.65 nm greater than at rest.(ABSTRACT TRUNCATED AT 400 WORDS)

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Structure of the myosin head in solution and the effect of light chain 2 removal

Cited by 6 publications

References 36 publications

The radius of gyration of native and reductively methylated myosin subfragment-1 from neutron scattering

The radius of gyration of native and reductively methylated myosin subfragment-1 from neutron scattering

Lattice spacing changes accompanying isometric tension development in intact single muscle fibers

Time-resolved X-ray diffraction studies of myosin head movements in live frog sartorius muscle during isometric and isotonic contractions

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