Heterodimer interface

The earlier computational studies (151,152,175,184,185) considered both domain-swapped and contact dimers as equally possible mechanisms of GPCR oligomerization. In contrast, the later computational studies on GPCR oligomerization (186-189) take into account only the hypothesis of contact dimers, supported by the more recent experimental evidence. For the prediction of heterodimer interfaces, the recent studies use a modified CMA methodology, termed subtractive correlated mutation (SCM) analysis (187,188). A similar method for the identification of physically interacting protein pairs has recently been reported in the literature (180). 

D. 3F4 Epitope Concealed in PrPSc Exposed at Heterodimer Interface... 

Previous molecular modeling suggests that the heterodimer interface is at residues Alall8-Alal33 (Warwicker, 2000). As modeled, this domain is... 

Inouye, H., and Kirschner, D. A. (2003). X-ray fibre diffraction analysis of assemblies formed by prion-related peptides Polymorphism of the heterodimer interface between PrPC and PrPSc. Fibre Diffract. Rev. 11, 102-112. 

RING/E2 interactions have also been studied with BRCAl. This E3 is unique in that it must heterodimerize with a second RING-domain protein, BARDl, in order to display maximal E3 activity [110]. Even though the heterodimer interface leaves... 

In summary, a DNA-supported asymmetric interface located within the DNA-binding domains of these nuclear receptors provides the molecular basis for receptor heterodimers to distinguish between closely related response elements. RXR can provide a repertoire of different dimerization surfaces, each one unique for a specific partner, allowing dimers to form that are adapted to the length of the spacer region in their corresponding response elements. 

FIG. 25 (a) Schematic representation for a photocatalytic mechanism based on shuttle photosensitizers at liquid-liquid interfaces. (Reprinted with permission from Ref. 182. Cop5right 1999 American Chemical Society.) (b) This mechanism is compared to the photo-oxidation of 1-octanol by the heterodimer ZnTPPS-ZnTMPyP in the presence of the redox mediator ZnTPP. (From Ref. 185.)... 

The hydroxylase component (MMOH) is composed of two a(3y protomers which use protein contacts between each of the a and (3 subunits along a two-fold symmetry axis to form an ot2[S2Y2 heterodimer. The interface between the two protomers forms a large cleft within which the MMOR is thought to dock. The diiron centre is located within a four-helix bundle made up of helices B, C, E and F of the a subunit. Helices E and F are on the surface of the hydroxylase, forming part of the rim of the cleft with the diiron centre some 12 A beneath this rim. Figure 13.25 compares the four-helix bundles that contain the diiron centres in six representatives of the superfamily. 

Enzymes may exist as simple monomers, or as homo- or heterodimers, or as multimers. In multimeric enzymes, each component monomer may possess a catalytic site alternatively, the catalytic site may be located at the interface between two or more monomers, or only one monomer of a heteromultimer may possess an active site. It is not uncommon in dimeric or multimeric enzymes containing two or more active sites for some degree of cooperativity to exist between the sites, with respect to the substrate binding or substrate turnover number (Monod et ah, 1965). 

HTI-286 binds to the tubulin heterodimer and induces formation of 13-membered tubulin rings [138], Photoaffinity labeling with analogues of HTI-286 mapped to residues of a-tubulin close to the interdimer interface [139], Competitive binding assays with dolastatin-10, cryptophycin A, vinblastine, PTX and colchicines, indicate that the hemiasterlins bind in a subsite of the Vinca domain, which is located at the interdimer interface [28],... 

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