ORGN 732 |
| Andrew Hagarman1, Tom Measey1, Fatma Eker2, Kai Griebenow3, and Reinhard Schweitzer-Stenner1. (1) Department of Chemistry, Drexel University, 32nd and Chestnut Street, Philadelphia, PA 19104, (2) Department of Biology, Drexel University, 32nd and Chestnut Streets, Philadelphia, PA 19104, (3) Department of Chemistry, University of Puerto Rico, Rio Piedras Campus, San Juan, PR 00931 |
| Electronic Circular Dichroism is a standard technique used to study the secondary structure of peptides and proteins. In order to determine the contribution of individual residues to the CD signal of polypeptides we measured the ECD spectra of a series of 17 cationic, AX and XA dipeptides in D22, where X represents a set of non-aromatic residues. For the XA peptides we found a substantial population of the polyproline II (PPII) conformation. The strength of the PPII signals suggests a hierarchy GA> CA, AA> RA> PA> DA, AL, SA> MA, VA, EA> AV, LA, KA, AK> AS> AG, where GA is the highest with respect to the PPII propensity. Surprisingly, we found that corresponding XA and AX peptides do not always exhibit even similar CD spectra. This can be rationalized either by invoking context dependence structural propensities, or in terms of different contributions of the two residues to the total ECD spectrum of a dipeptide. |
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Proteins, Peptides, and Amino Acids
8:00 AM-12:00 PM, Thursday, August 26, 2004 Pennsylvania Convention Center -- 201A, Oral
Division of Organic Chemistry |