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Most Requested Journal Articles 3Q04-Chemistry and Related Science

Following is one of the journal articles most requested by researchers using CAS online services.

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CAS indexed 17 chemical substances from this document. CAS subject entries for this document include: Protonation; Denaturation; Denaturation enthalpy; and 9 additional concepts.

CAPLUS COPYRIGHT 2004 ACS on STN

TITLE:	Toward catalytic rigid-rod .beta.-barrels: a hexamer with multiple histidines
AUTHOR(S):	Das, Gopal; Sakai, Naomi; Matile, Stefan
CORPORATE SOURCE:	Department of Organic Chemistry, University of Geneva, Geneva, Switz.
SOURCE:	Chirality (2002), 14(1), 18-24 CODEN: CHRLEP; ISSN: 0899-0042
PUBLISHER:	Wiley-Liss, Inc.
LANGUAGE:	English

ABSTRACT:
Rigid-rod .beta.-barrels are composed of interdigitating, short, amphiphilic peptide strands that are flanked by stabilizing rigid-rod "staves.". As a first step toward the construction of catalytic rigid-rod .beta.-barrels, we here report synthesis and study of a new barrel designed to comprise alternating leucine and histidine residues at the inner and lysine and glutamate residues at the outer barrel surface. Synthesis of p-octiphenyls with lateral tripeptide strands followed procedures described previously. Barrel formation by programmed assembly of complementary tripeptide-p-octiphenyl rods was monitored by CD (CD). CD-mixing curves (Job-plots) were consistent with 1:1-stoichiometry. Guanidinium chloride denaturation expts. gave a .DELTA.GH20 = -1.8 kcal mol-1 with a C50 = 1.9 M. Size exclusion chromatog. suggested quant. formation of a hexamer. Facile barrel deconstruction by acid and divalent cations demonstrated the presence of internal, nonproximal histidines. Inclusion complex formation with fluorescent guests corroborated internal hydrophobicity of .beta.-barrel hosts and potential for intratoroidal catalysis.