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Please use this identifier to cite or link to this item: http://dspace.library.iitb.ac.in/jspui/handle/10054/3780

Title: Cured of "Stickiness", Poly-L beta-Hairpin is Promoted with LL-to-DD Mutation as a Protein and a Hydrolase Mimic
Authors: PATEL, K
GOYAL, B
KUMAR, A
KISHORE, N
DURANI, S
Keywords: de-novo design
aromatic interactions
molecular-dynamics
peptide
folds
recognition
miniprotein
simulation
principles
residues
Issue Date: 2010
Publisher: AMER CHEMICAL SOC
Citation: JOURNAL OF PHYSICAL CHEMISTRY B, 114(50), 16887-16893
Abstract: The planar ribbon of the poly-L beta-hairpin is modified to a local similar to 90 degrees bend by mutating a cross-strand pair of residues from LL to DD structure. The bend is furnished aromatic side chains in proximity of acid-base-nucleophile side chains, toward the possibility of catalyzed hydrolysis of an active-site-anchored substrate. Six sequences permuted in putative catalytic side chains are evaluated for activity and variability as hydrolase enzymes. Studies using CD, NMR, spectorofluorometry, ITC, and molecular dynamics establish that the sequences over the bent beta-hairpin are by and large aggregation-free folds soluble to at least millimolar concentration, and thus remarkably contrasted with "stickiness" of the canonical poly-L beta-hairpin. The heterochiral fold displays cooperative ordering and affinity for acetylcholine, p-nitrophenylacetate, and p-nitrophenylphosphate, presumably as the ligands in its aromatic pocket as a bent hairpin. The fold displays hydrolytic activity against p-nitrophenylacetate and manifests saturation kinetics with respect to substrate concentration. However, the catalysis power is feeble, which remains unaffected by repositioning acid-base-nucleophile side chains. Stereochemistry is proven to be critical in the balance between mutually competitive forces of polypeptide structure involved in guidance of folding or aggregation of the structure. Residue stereochemistry is confirmed in its value as the alphabet for design of protein folds to desired molecular shapes.
URI: http://dx.doi.org/10.1021/jp1062572
http://dspace.library.iitb.ac.in/xmlui/handle/10054/3780
http://hdl.handle.net/10054/3780
ISSN: 1520-6106
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