Transmembrane topography

Figure 7.4 Comparative schematic representation of the Dj ( ) and D (—) dopamine receptor. The figure attempts to highlight the major differences between extra- and intracellular loops, especially the intracellular loops between transmembrane sections 5 and 6 and the much longer C terminal of the Dj compared with the D2 receptor. It is based on the proposed topography of Sibley and Monsma (1992). The thickened length of the D2 receptor represents the amino-acid sequence missing in the short form of the receptor. No attempt has been made to show differences in amino-acid sequencing or transmembrane topography...

Fig. 1. Model for the transmembrane topography of the H -ATPase. OUT and IN indicate points of reference outside and inside an intact cell, respectively. See text for additional details.

Leng, X. H., Nishi, T., and Forgac, M. (1999). Transmembrane topography of the 100-kDa a subunit (Vphlp) of the yeast vacuolar proton-translocating ATPase./. Biol. Chem. 274, 14655-14661. 

The folded structure of chemokine receptors has not been determined however a model can be constructed for the transmembrane helices based on the known structure of rhodopsin (Unger et al., 1997). In addition, domain-specific antibodies have been used in some cases to establish the transmembrane topography of N- and C-termini and the loop regions, which are consistent with the rhodopsin model. Early biochemical... 

Several human receptors for the neurohypophyseal hormones have been cloned and the sequences elucidated. The human V2 receptor for antidiuretic hormone presumably contains 371 amino acids and seven transmembrane segments and activates cycHc AMP (76). The oxytocin receptor is a classic G-protein-coupled type of receptor with a proposed membrane topography also involving seven transmembrane components (84). A schematic representation of the oxytocin receptor stmcture within the membrane is shown in Eigure 4 (85). 

Rothnie, A., Storm, J., Campbell, J., Linton, K.J., Kerr, I.D. and Callaghan, R. (2004) The topography of transmembrane segment six is altered during the catalytic cycle of P-glycoprotein. Journal of Biological Chemistry, 279, 34913-34921. 

Fig. 3.2. Model of the cytochrome oxidase monomer. The structural model of the membrane-bound cytochrome oxidase monomer that has emerged from image reconstruction studies of two-dimensional crystals [102-106] is an asymmetric Y -shaped molecule (see also Ref. 99). A considerable part protrudes on the cytoplasmic side of the membrane, but only little on the M side. In the membrane there are two separated domains. Chemical labelling and cross-Unking studies (see Refs. 85, 92, 95, 96, 99 for reviews) have given at least a rough topography of the individual subunits. The protruding C-domain is made up mainly of subunits I, II, III and V, while the aqueous M-domain is largely due to subunit IV. The two membranous domains are formed by subunits I and III, but also subunits II, IV, Villa and Vlllb (Table 3.3) probably contribute with 2, 1, 1 and 1 transmembranous polypeptide segments, respectively.

Fig. 1 Topography of the sweet taste receptor. The sweet taste receptor is an integral membrane protein complex composed of two subunits, T1R2 (red) and T1R3 (blue). Each subunit has three main domains a large, extracellular Venus-flytrap domain (VFD) at the amino end of the protein a seven-transmembrane helical domain typical of G-protein-coupled receptors on the carboxyl end and a cysteine-rich linker domain that connects the other two domains...

Nakatani, Y, Yamamoto, M., Diyizou, Y. et al. (1996). Studies on the topography of biomembranes regioselective photolabelling in vesicles with the tandem use of cholesterol and a photoactivable transmembrane phospholipidic probe. Chemistry - a European Journal, 2, 129-38. 

Tae GS, Black MT, Cramer WA et al. Thylakoid membrane protein topography transmembrane orientation of the chloroplast cytochrome b559 psbE gene product. Biochemistry 1988 27 9075-9080. 

The majority of Man-T are membrane proteins Man-T activities sediment with membranes, and the available amino acid sequences of Man-T contain one or more predicted transmembrane helices. In a few cases, the transmembrime topography of... 

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