| Structural highlights
2w4u is a 36 chain structure with sequence from Gallus gallus and Oryctolagus cuniculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Related: | 1tnq, 2aso, 1wua, 1o18, 2d1k, 1ncx, 1ew7, 2a5x, 2v52, 1j6z, 1npq, 1atn, 1ytz, 1s22, 1t44, 1zac, 2ff6, 1o1f, 2tma, 1blq, 1jc2, 1o19, 1o1e, 1p8z, 1o1c, 2vcp, 1o1g, 1vdi, 1qz6, 1avs, 1lcu, 2a42, 1top, 1ijj, 1o1a, 1tnx, 1m8q, 1uy5, 1rfq, 1ma9, 1rdw, 1o1b, 1o1d, 1ncy, 2a40, 1qz5, 1nwk, 1smg, 1sqk, 1tnp, 1pon, 1tnw, 2ff3, 1mvw, 1eqy, 2fxu, 2v51, 1kxp, 2asp, 2d3e, 1rgi, 1y64, 1ncz, 1alm |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[TPM1_RABIT] Binds to actin filaments in muscle and non-muscle cells. Plays a central role, in association with the troponin complex, in the calcium dependent regulation of vertebrate striated muscle contraction. Smooth muscle contraction is regulated by interaction with caldesmon. In non-muscle cells is implicated in stabilizing cytoskeleton actin filaments. [TNNC2_CHICK] Troponin is the central regulatory protein of striated muscle contraction. Tn consists of three components: Tn-I which is the inhibitor of actomyosin ATPase, Tn-T which contains the binding site for tropomyosin and Tn-C. The binding of calcium to Tn-C abolishes the inhibitory action of Tn on actin filaments. [TNNI2_CHICK] Troponin I is the inhibitory subunit of troponin, the thin filament regulatory complex which confers calcium-sensitivity to striated muscle actomyosin ATPase activity. [TNNT3_CHICK] Troponin T is the tropomyosin-binding subunit of troponin, the thin filament regulatory complex which confers calcium-sensitivity to striated muscle actomyosin ATPase activity. [ACTS_RABIT] Actins are highly conserved proteins that are involved in various types of cell motility and are ubiquitously expressed in all eukaryotic cells.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The application of rapidly applied length steps to actively contracting muscle is a classic method for synchronizing the response of myosin cross-bridges so that the average response of the ensemble can be measured. Alternatively, electron tomography (ET) is a technique that can report the structure of the individual members of the ensemble. We probed the structure of active myosin motors (cross-bridges) by applying 0.5% changes in length (either a stretch or a release) within 2 ms to isometrically contracting insect flight muscle (IFM) fibers followed after 5-6 ms by rapid freezing against a liquid helium cooled copper mirror. ET of freeze-substituted fibers, embedded and thin-sectioned, provides 3-D cross-bridge images, sorted by multivariate data analysis into approximately 40 classes, distinct in average structure, population size and lattice distribution. Individual actin subunits are resolved facilitating quasi-atomic modeling of each class average to determine its binding strength (weak or strong) to actin. approximately 98% of strong-binding acto-myosin attachments present after a length perturbation are confined to "target zones" of only two actin subunits located exactly midway between successive troponin complexes along each long-pitch helical repeat of actin. Significant changes in the types, distribution and structure of actin-myosin attachments occurred in a manner consistent with the mechanical transients. Most dramatic is near disappearance, after either length perturbation, of a class of weak-binding cross-bridges, attached within the target zone, that are highly likely to be precursors of strong-binding cross-bridges. These weak-binding cross-bridges were originally observed in isometrically contracting IFM. Their disappearance following a quick stretch or release can be explained by a recent kinetic model for muscle contraction, as behaviour consistent with their identification as precursors of strong-binding cross-bridges. The results provide a detailed model for contraction in IFM that may be applicable to contraction in other types of muscle.
Structural Changes in Isometrically Contracting Insect Flight Muscle Trapped following a Mechanical Perturbation.,Wu S, Liu J, Reedy MC, Perz-Edwards RJ, Tregear RT, Winkler H, Franzini-Armstrong C, Sasaki H, Lucaveche C, Goldman YE, Reedy MK, Taylor KA PLoS One. 2012;7(6):e39422. Epub 2012 Jun 25. PMID:22761792[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Wu S, Liu J, Reedy MC, Perz-Edwards RJ, Tregear RT, Winkler H, Franzini-Armstrong C, Sasaki H, Lucaveche C, Goldman YE, Reedy MK, Taylor KA. Structural Changes in Isometrically Contracting Insect Flight Muscle Trapped following a Mechanical Perturbation. PLoS One. 2012;7(6):e39422. Epub 2012 Jun 25. PMID:22761792 doi:10.1371/journal.pone.0039422
|
