Faculty Collaboration Database

Low frequency resonance Raman spectra of isolated alpha and beta subunits of hemoglobin and their deuterated analogues. Biopolymers 2006 Dec 05;83(5):455-66

Date

07/18/2006

Pubmed ID

16845667

DOI

10.1002/bip.20573

Scopus ID

2-s2.0-33845232631 (requires institutional sign-in at Scopus site)   18 Citations

Abstract

In an attempt to gain further insight into the nature of the low frequency vibrational modes of hemoglobin and its isolated subunits, a comprehensive study of several different isotopically labeled analogues has been undertaken and is reported herein. Specifically, the resonance Raman spectra, between 200 and 500 cm(-1), are reported for the deoxy and ligated (CO and O2) forms of the isolated alpha and beta subunits containing the natural abundance or various deuterated analogues of protoheme. The deuterated protoheme analogues studied include the 1,3,5,8-C2H3-protoheme (d12- protoheme), the 1,3-C2H3-protoheme (1,3-d6-protoheme), the 5,8-C2H3-protoheme (5,8-d6-protoheme), and the meso-C2H4-protoheme (d4-protoheme). The entire set of acquired spectra has been analyzed using a deconvolution procedure to help correlate the shifted modes with their counterparts in the spectra of the native forms. Interestingly, modes previously associated with so-called vinyl bending modes or propionate deformation modes are shown to be quite sensitive to deuteration of the peripheral methyl groups of the macrocycle, shifting by up to 12-15 cm(-1), revealing their complex nature. Of special interest is the fact that shifts observed for the 1,3-d6- and 5,8-d6-protoheme analogues confirm the fact that certain modes are associated with a given portion of the macrocycle; i.e., only certain modes shift upon deuteration of the 1 and 3 methyl groups, while others shift upon deuteration of the 5 and 8 methyl groups. Compared with the spectra previously reported for the corresponding myoglobin derivatives, the data reported here reveal the appearance of several additional features that imply splitting of modes associated with the propionate groups or that are indicative of greater distortion of the heme prosthetic groups.

Author List

Podstawka E, Mak PJ, Kincaid JR, Proniewicz LM

Author

James Kincaid PhD Department Chair and Professor, Biophysical Chemistry in the Chemistry department at Marquette University

MESH terms used to index this publication - Major topics in bold

Deuterium
Heme
Hemoglobins
Molecular Structure
Protein Conformation
Protein Subunits
Spectrum Analysis, Raman
Vibration