NEXAFS Characterization of Poly(amino acids)

Published

October 12, 2021

Author(s)

N T. Samuel, Daniel A. Fischer, David G. Castner

Abstract

The near-edge x-ray absorption fine structure (NEXAFS) spectra of poly(amino acids) at the carbon, nitrogen and oxygen k-edges are investigated in this study. The poly(amino acid) NEXAFS spectra at the k-edges closely resemble the spectra of the corresponding monomeric amino acids and most of the peaks in the poly(amino acid) spectra could be assigned to specific transitions based on these earlier monomeric amino acid studies. All the poly(amino acids) exhibited NEXAFS peaks corresponding to ?*C=O and ?*C-C resonances in the carbon spectra with intense ?* and broad ?* resonances in both the nitrogen and oxygen spectra. Peaks corresponding to ?*C=C, ?*C=N, ?*C-OH, ?*C-N and the C-H Rydberg resonances were also observed in some of the poly(amino acid) carbon k-edge spectra. The present study extends the early NEXAFS experiments on monomeric amino acids by obtaining a more comprehensive set of carbon, nitrogen and oxygen k-edge spectra from amino acid homopolymers containing peptide bonds. In addition, it also addresses the assignment of the amide ?* feature in the amino acid nitrogen k-edge, which has been the subject of some disagreemnt in previous studies. The results from this study are expected to complement the extensive previous analysis of amino acids by NEXAFS and also provide detailed interpretation of adsorbed protein spectra.

Citation

Surface and Interface Analysis

Pub Type

Journals

Keywords

biological molecules-proteins, NEXAFS, XPS

Citation

Samuel, N. , Fischer, D. and Castner, D. (2021), NEXAFS Characterization of Poly(amino acids), Surface and Interface Analysis (Accessed December 15, 2024)