Open AccessStructural characterization of a β-turn mimic within a protein–protein interface
Author(s) -
Björn Eckhardt,
Wolfgang Große,
LarsOliver Essen,
Armin Geyer
Publication year - 2010
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.1004187107
Subject(s) - turn (biochemistry) , trimer , chemistry , side chain , protein engineering , protein structure , dipeptide , molecular mimicry , mimicry , crystallography , stereochemistry , peptide , biophysics , biochemistry , biology , organic chemistry , dimer , ecology , antigen , genetics , enzyme , polymer
β-turns are secondary structure elements not only exposed on protein surfaces, but also frequently found to be buried in protein–protein interfaces. Protein engineering so far considered mainly the backbone-constraining properties of synthetic β-turn mimics as parts of surface-exposed loops. A β-turn mimic, Hot═Tap, that is available in gram amounts, provides two hydroxyl groups that enhance its turn-inducing properties besides being able to form side-chain-like interactions. NMR studies on cyclic hexapeptides harboring the Hot═Tap dipeptide proved its strong β-turn-inducing capability. Crystallographic analyses of the trimeric fibritin-foldon/Hot═Tap hybrid reveal at atomic resolution how Hot═Tap replaces a βI’-turn by a βII’-type structure. Furthermore, Hot═Tap adapts to the complex protein environment by participating in several direct and water-bridged interactions across the foldon trimer interface. As building blocks, β-turn mimics capable of both backbone and side-chain mimicry may simplify the design of synthetic proteins.