G protein structure

G proteins regulate intracellular concentrations of second messengers. G proteins control intracellular cAMP concentrations by mediating the ability of neurotransmitters to activate or inhibit adenylyl cyclase. The mechanism by which neurotransmitters stimulate adenylyl cyclase is well known. Activation of those neurotransmitter receptors that couple to Gs results in the generation of free G(IS subunits, which bind to and thus directly activate adenylyl cyclase. In addition, free Py-subunit complexes activate certain subtypes of adenylyl cyclase (see Ch. 21). A similar mechanism appears to be the case for G(IO f, a type of G protein structurally related to G that is enriched in olfactory epithelium and striatum (Ch. 50). 

Wensel, T. (1999) Introduction to cellular signal transduction. (Sitaramayya, A. ed.) Heterotiimeiic G-Proteins Structure, regulation and signahng mechanisms. Introductory Signal Transduction pp. 29 6. Birkhanser, Boston, MA. 

AZIDO PHOTOAFFINITY REAGENTS 2-Azido-NAD as G-protein structure probe, AZIDO PHOTOAFFINITY REAGENTS... 

Prentiss, M.C., Wales, D.J., Wolynes, P.G. Protein structure prediction using basin-hopping. J. Chem. Phys. 2008, 128, 225106. 

Cabrera-Vera TM et al Insights into G protein structure, function, and regulation. Endocr Rev 2003 24 765. [PMID 14671004]... 

The reaction cycle of the heterotrimeric G proteins involves the formation and breaking of numerous protein-protein contacts. In a dynamic way, protein-protein interactions are formed and resolved during the cycle, defining distinct states of the G protein and leading to new functions and reactions. A wealth of structural information is now available for most of the distinct functional states of the G proteins. Structures are available for... 

Petsko G A and Ringe D 1984 Fluctuations in protein structure from x-ray diffraction A. Rev. Biophys. Bioengng. 13 331-71... 

Pemtz M 1992. Protein Structure. New Approaches to Disease And Therapy. New York, W H Freeman. Schulz G E and R H Schirmer 1979. Principles of Protein Structure. New York, Springer-Verlag. 

Bryngelson J D, J N Onuchic, N D Socci and P G Wolynes 1995. Funnels, Pathways, and the Energy Landscape of Protein Folding A Synthesis. Proteins Structure, Function and Genetics 21 167-195. 

Cuff IA and G J Barton 1999. Evaluation and Improvement of Multiple Sequence Methods for P Secondary Structure Prediction. Proteins Structure, Function and Genetics 34 508-519. 

Maiorov V N and G M Crippen 1994. Learning About Protein Folding via Potential Functions. Proteins Structure, Function and Genetics 20 167-173. 

Mosimann S, S Meleshko and M N G Jones 1995. A Critical Assessment of Comparative Molecular Modeling of Tertiary Structures of Proteins. Proteins Structure, Function and Genetics 23 301-317. 

Noble M E M, R K Wierenga, A-M Lambeir, F R Opperdoes, W H Thunnissen, K H Kalk, H Groendijk and W G J Hoi 1991. The Adaptability of the Active Site of Trypanosomal Triosephosphate Isomerase as Observed in the Crystal Structures of Three Different Complexes. Proteins Structure, Function and Genetics 10 50-69. 

Boresch S, G Archontis and M Karplus 1994. Free Energy Simulations The Meaning of the Indi-. id Contributions from a Component. Analysis. Proteins Structure, Function and Gau tics 20 25-33. 

Einally, structural properties that depend directly neither on the data nor on the energy parameters can be checked by comparing the structures to statistics derived from a database of solved protein structures. PROCHECK-NMR and WHAT IE [94] use, e.g., statistics on backbone and side chain dihedral angles and on hydrogen bonds. PROSA [95] uses potentials of mean force derived from distributions of amino acid-amino acid distances. 

Richardson, J.S., Richardson, D.C. Principles and patterns of protein conformation. In Prediction of Protein Structure and the Principles of Protein Conformation (ed. Fasman, G.D.), pp. 1-98. New York Plenum, 1989. 

Schulz, G.E., Schirmer, R.H. Principles of Protein Structure. New York Springer, 1979. 

Matthews, B.W., Rossmann, M.G. Comparison of protein structures. Methods Enzymol. 115 397-420, 1985. 

A second example of up-and-down p sheets is the protein neuraminidase from influenza virus. Here the packing of the sheets is different from that in RBP. They do not form a simple barrel but instead six small sheets, each with four P strands, which are arranged like the blades of a six-bladed propeller. Loop regions between the p strands form the active site in the middle of one side of the propeller. Other similar structures are known with different numbers of the same motif arranged like propellers with different numbers of blades such as the G-proteins discussed in Chapter 13. 

---