Leudn zipper

Answen Q Proteins with SH2 domains might bind to the insulin receptor substrate-1 (IRS-1) to transmit signals from the insulin receptor, a tyrosine kinase type of receptor. PI-3 kinase is an example of an SH2 domain protein. SH2 domains are not involved in DNA binding (choices A and D). Examples of protein domains that bind DNA include zinc fingers (steroid receptors), leudne zippers (CREB protein), and helix-turn-helbc proteins (homeodomain proteins),... 

Fig. 1.7. Basic leudne zipper and heltx-loop-heltx motif in complex with DNA. A) The basic leucine zipper of the transcription activator GCN4 of yeast consists of two slightly curved a-hehces, which dimerize with the help of the leucine zipper motif. The sequence specific binding of DNA occurs via the basic ends of the two helices. They insert themselves into the major groove of the DNA. B) The helix-loop-helix motif of the eucaryotic transcription factor Max complexed with DNA. Molscript drawing (Kraulis 1991).

Ellenberger, T. Getting a grip on DNA recognition structures of the basic region leudne zipper, and the basic region helix-loop-helix DNA-binding domains (1994) Curr. Op. Struct. Biol. 

Acharya A, Ruvinov SB, Moll JR, Vinson C. 2002. A hetero-dimerizing leudne zipper coiled coil system for examining the specificity of a position interactions Amino acids I, V, L, N, A, and K. Biochemistry 41 14122-14131. 

Reactive noncanonical amino adds have also been integrated into elastin-like protein polymers to enhance their application as biomaterials. The Tinell laboratory has used the photoreactive amino add p-azidophenylalanine to pattern elastin-like protein polymers on surfaces. " Zhang et d. used p-azidophenylalanine to photochemically cross-link an elastin-leudne zipper protein to a glass surface. A target protein linked to a second leudne zipper domain can then be captured from solution and patterned on the surface by dimerization of the leucine zipper domains. Carrico et al. used similar p-azidophenylalanine-fiinctionalized elastin protein polymers... 

Still another variation of this interaction comes into play, when during the approach, a new type of i nthon appears, and the q nthons match afterwards. For sample in the Hodges superhelical structure (Fig. 13.16), only after formation of the a-helices does it turn out that the leucine and valine side chains of one helix match perfectly similar synthons of the second helix ( leudne-valine zipper ). 

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