Motion in Citrate Synthase [cs]

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Classification Known Domain Motion, Shear Mechanism [D-s-2]

Structures
1CTS Conformation 1 [ PartsList ]
3CTS Conformation 2

Description
Shear motions at many helix-helix interfaces shift mainchain atoms up to 10 A. Citrate synthase is one of the clearest examples of a domain closure occurring through shear motions. The molecule is a dimer, and each monomer comprises a large domain, containing 15 helices, and a small domain, containing 5 helices, with the active site cleft between them. The domain closure involves the small domain closing over the large one, burying the substrates in the active site. An extensive interface between the large and small domains prevents closure taking place through a hinge mechanism. Closure is produced by the summation of many small shear motions between pairs of packed helices. The overall motion results in a helix on the far side of the small domain shifting by 10 A and rotating by 28 degrees, thereby moving an adjacent loop over the active site. Each local shear motion involves one helix moving relative to another by main-chain rotations and shifts of up to 13 degrees and 1.8 A. To a good approximation, the main chain of each helix moves without deformation as a rigid body. The shear motions are facilitated by small deformations in the loops linking the helices.

Particular values describing motion
Experimental Methods = x (Traditional x-ray)
Creation Date = 19970822
Modification Date = 19970822

References
A M Lesk and C Chothia (1984). Mechanisms of Domain Closure in Proteins. J. Mol. Biol. 174: 175-91. [Medline info for 94082290]
S Remington, G Wiegand and R Huber (1982). Crystallographic refinement and atomic models of two different forms of citrate synthase at 2.7 and 1.7 Å resolution. J. Mol. Biol. 158: 111-152. [Medline info for 94082290]

Data and Graphics
Graphic-2 Schematic showing helices in citrate synthase (from Lesk & Chothia, 1984).
Graphic-3 Schematic (from Lesk & Chothia, 1984) showing local movement (rot. and trans.) of pairs of helices (left) and overall movement (right) of these same helices.
Graphic-1 Overall motion.

GO terms associated with structures
Molecular functiontransferase activity, transferring acyl groups, acyl groups converted into alkyl on transfer, citrate (Si)-synthase activity
Cellular componentcytoplasm
Biological processtricarboxylic acid cycle, main pathways of carbohydrate metabolism

Morphs

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Best representative
Morph Morph name Structure #1 Structure #2 Residues
Citrate Synthase 4cts [ ] 1cts [ ] 437

User-submitted morphs
Morph Morph name Structure #1 Structure #2 Residues
479211-18847 Citrate Cynthase upload [ A ] upload [ A ] 429
596852-21627 Citrate Synthase 1cts [ A ] 4cts [ A ] 437
611097-7064 Citrate Synthase 1cts [ A ] 5cts [ A ] 429
155516-13962 citrate synthase 5csc [ A ] 1csh [ A ] 435
155732-14014 citrate synthase 5csc [ A ] 1csh [ A ] 435
157745-15678 citrate Synthase 1cts [ A ] 1csh [ A ] 435
797157-24794 citrate synthase upload [ B ] upload [ B ] 379
823867-30466 citrate synthase 5csc [ A ] 6csc [ A ] 437
316976-20725 Citrate synthase 5csc [ A ] 6csc [ A ] 437
035457-20647 Citrate Synthase apo to ternary upload [ B ] upload [ B ] 379

Automatic morphs
Morph Morph name Structure #1 Structure #2 Residues
va1ctsA-2ctsA Citrate Synthase (E.C. 4.1.3.7 1cts [ A ] 2cts [ A ] 437
va4ctsB-1ctsA Citrate Synthase (E.C. 4.1.3.7 4cts [ B ] 1cts [ A ] 437
va4ctsA-1ctsA Citrate Synthase (E.C. 4.1.3.7 4cts [ A ] 1cts [ A ] 437

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Copyright 1995-2005 M. Gerstein, W. Krebs, S. Flores, N. Echols, and others
Email: Mark.Gerstein _at_ yale.edu