Rigid body movement

How does the rigid body movement of the switch-2 cluster comply with its interactions with the rest of the motor domain Regarding the main chain connectivity, such a movement requires flexible adaptors at both ends of the cluster. At the N-terminus, loop LI 1 obviously fulfills this function. At the other end, loop L13 (between a5 and strand jS8 of the central /i-sheet) may provide sufficient flexibility. Loop L13 contains two... 

Two independent strategies, modulation of tertiary contact interaction and direct distance mapping, provide compelling evidence for a dominant rigid-body movement of TM6 near the cytoplasmic surface, with smaller but significant movements of TM1, TM2, TM3, and TM7. 

In the complexes of RmL with inhibitors, the central, helical part of the lid (residues 85-92) is transported 8 A across the molecular surface (Fig. 9). During this change the helix actually rolls back from the active site, rotating by 167° about its own axis. This dramatic shift is a rigid body movement when the two helices, in the native and inhibited enzymes, are superimposed, the root-mean-square deviation for all main-chain atoms is 0.31 A, well within the accuracy limits imposed by the experimental methods used. 

Nuclear motion does not cause rigid body movement (translation) or rotation of molecules. 

THE ESTIMATION OF RIGID-BODY-MOVEMENTS AROUND A 3D-AXIS... 

Bleich, Diner (1989) describe aii approach for the solution of a rigid—body—movement in that case that there are only two epochs. If the body is discreted by a number of p points, two consecutive epochs i and i+1 contain the coordinates... 

Next this rotation axis will be derivated. It is a fact that the axis will be constant during the rigid—body-movement. So we can ascertain the axis by solving the following special eigenvalue problem... 

Although a spatial rigid—body-movement has only 6 degrees of freedom the axial model (17) contains the following 8 parameters... 

A comparison with the general model of a rigid-body-movement (2) yields the relation between the position vector a and the translation vector t... 

Kinematics of the Lumbosacral Junction. The second major biomechanical fundamental of the spine is to allow movement. The study of rigid body movement is kinematics. It is important to realize that as a vertebra moves from one position to the next, this motion can be described in a variety of ways. By assuming the vertebra is a rigid body, we may describe its motion in terms of rotation and translation. Note that translation is dependent upon which point on the vertebra is selected. In two dimensions, the... 

In the large domain of citrate synthase there are small movements. In the small domain a large change occurs, which can be described as a rigid body movement in a first approximation. However, on detailed inspection one finds that there are small structural changes all over the molecule, particularly in the small domain, but also some in the large domain. So it is only to a first approximation a two state model. One must postulate this because the environment of the small domain in the open state faces the solvent much more than in the closed state, where it is in contact with the large domain. This must be reflected in the internal conformation, and this is actually what we see. Nevertheless, I think it is useful to talk of the two state model. 

ANS I thank you for this information. It wouldn t be difficult to choose clamping or fixation or hinging or any other boundary condition as long as it can prevent rigid body movements. We need to have more than one point fixed in space in order to prevent rigid body movement and I don t know at... 

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