ISSN:
0887-3585
Keywords:
phosphorylation
;
tyrosine
;
cis-peptide
;
exocytosis
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
Seven proteins each contain 8 to 52 tandem repeats of a unique class of oligopeptide. The consensus peptide for each is rhodopsin Tyr Pro Pro Gln Glysynapto-physin Tyr Gly Pro Gln Glysynexin Tyr Pro Pro Pro Pro Glygliadin Tyr Pro Pro Pro Gln ProRNA polymerase II Tyr Ser Pro Thr Ser Pro Serhordein Phe Pro Gln Gln Pro Gln Gln Progluten Tyr Pro Thr Ser Pro Gln Gn Gly TyrAlthough there is obvious variations of sequence and of length, the penta-to nonapeptides share an initial Tyr(or Phe) and have high Pro contents and abundant Gly, Gln, and Ser. We have evaluated helical models that both recognize the uniqueness of these sequence repeats and accommodate variations on the basic theme.We have developed a group of related heical model for these proteins with about three oligopeptide repeats per turn of 10-20 Å. These models share several common features: Most of the φ dihedral angels are -54°, to accommodate Pro at all positions expect the first (Tyr). Except for the β-turns, most ψ dihedral angles are near +140° as found in polyproline. Each oligopeptide has at least one β-turn; several have two. Some contains a cis-Tyr, Pro peptide bond; a few have a cis-bond plus one β-turn. Tyr side chains vary from totally exposed to buried within the helices and could mode to accommodate either external hydrophobic interactions or phosphorylation. The several related structures seem to be readily interconverted without major change in the overall helical parameters, and therein may lie the key to their functions.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prot.340070204
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