Order to disorder transition

Davis, K., Russel, W., and Glantschnig, W., Disorder-to-order transitions in settling suspensions of colloidal sihca x-ray measurements. Science, 245, 507, 1989. Bartlett, R, Pusey, R, and OttewiU, R., Colloidal crystallization under time-averaged zero gravity, Langmuir, 1, 213, 1991. 

Semirigid domains with hinges (GroEL, Fj-ATPase) Disorder to order transition (Kinesin)... 

When a film that was deposited at a relative humidity of 40% was exposed to an environment with a relative humidity of 85% 10 min after deposition, a phase change from 2-D hexagonal to cubic was observed. Other relative humidity changes led to a disordered to ordered transition in the film. 

Y. Zhou, C. K. Hall and M. Karplus. First-order disorder-to-order transition in an isolated homopolymer model. Physical Review Letters, 77 (1996), 2822. 

Disorder-to-order transition covering active site (triose phosphate isomerase, penicil-lopepsin)... 

Disorder-to-order transition as part of enzyme activation (trypsinogen-trypsin)... 

The occurrence of disorder-to-order transitions involving segments of a protein, the remainder of which has a well-defined conformation, has been documented in crystal structures of a variety of systems. The segments involved may be at the N terminal or the C terminal end (disordered arm ) or in the middle of the polypeptide chain (disordered loop ). The length of the disordered segment varies from five or six amino acids to a sizable portion of the... 

Another type of disorder-to-order transition is the so-called loop-cap transition in certain enzymes.279,280 This structural change is associated with a highly mobile loop of residues, from 6 to 12 amino acid residues in length, that are located near the active site. Such a structural feature has been identified in the enzyme triose phosphate isomerase (TIM). TIM makes an especially interesting case study for theoretical analysis of the loop-cap transition because there exist X-ray,279,313 kinetic,121 and thermodynamic data121 for this enzyme. 

It is likely that the entropy loss in closing the loop partially offsets the en-thalpic gain on binding. In this way the enzyme can be highly specific, yet not bind the substrate too strongly. Further, it is possible that the disorder-to-order transition in the formation of the enzyme substrate complex raises its... 

Of particular significance are disorder-to-order transitions related to association part or aU of the polypeptide chain in one component is unfolded in the free form and becomes structured in the complex. We took the trypsin—PTI complex as an example of rigid-body association. The closely related trypsinogen—PTI complex is an example of a disorder-to-order transition. Its structure is essentially identical to that of trypsin— PTI, yet, in free trypsinogen, loops amounting to about one-quarter of the polypeptide chain are fuUy disordered. In the presence of PTI, they... 

Conformational changes play an even more important role in protein-DNA recognition. As in protein-protein interactions, extensive changes accompany the formation of large interfaces disordered segments of the polypeptide chain become ordered, and whole subunits and domains move and loops rearrange on the protein surface (Nadassy et al., 1999). In protein-DNA interactions, the abundance of disorder-to-order transitions is probably underestimated, because many proteins that undergo such transitions do not yield useful crystals or NMR spectra in the free state. 

The interface between thrombin and ornithodorin and the Go—Gay interface in transducin are comparable in size to subunit interfaces in oligomeric proteins which are permanent assemblies (Jones and Thornton, 1995, 1996 Ford etal., 1998). The average homodimer in the sample analyzed by Jones and Thornton (1996) buries 3370 A, and the average antigen-antibody complex buries 1550 A (note that these authors quote interface areas per subunit, which is 5/2 in our notation). The assembly of oligomeric proteins is usually accompanied by major conformational changes and/or disorder-to-order transitions. These events also accompany the formation of protein-protein complexes with large interfaces. 

Thus, hirudin, as shown in Fig. 9, undergoes a disorder-to-order transition when forming a 3300-A interface with thrombin, as NMR studies of the free protein indicate that the C-terminal tail is disordered in solution. The structure of free ornithodorin is not known, but the two PTI-Hke domains are unlikely to adopt the same relative position as in Fig. 9. 

Devarakonda, S., Gupta, K., Chalmers, M.J., et al. (2011) Disorder-to-order transition underlies the structural basis for the assembly of a transcriptionally active PGC-lo/ERRy complex. Pmc Natl Acad Sci USA, 108 (46), 18678-18683. 

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