Biophysical Journal 70: 1214-1229 (1996)
© 1996 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kushkuley, B Articles by Stavrov, S S Search for Related Content PubMed PubMed Citation Articles by Kushkuley, B Articles by Stavrov, S S

Theoretical study of the distal-side steric and electrostatic effects on the vibrational characteristics of the FeCO unit of the carbonylheme proteins and their models.

Sackler Institute of Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Israel.

ABSTRACT

The vibronic theory of activation and quantum chemical intermediate neglect of differential overlap (INDO) calculations are used to study the activation of carbon monoxide (change of the C-O bond index and force field constant) by the imidazole complex with heme in dependence on the distortion of the porphyrin ring, geometry of the CO coordination, iron-carbon and iron-imidazole distances, iron displacement out of the porphyrin plane, and presence of the charged groups in the heme environment. It is shown that the main contribution to the CO activation stems from the change in the sigma donation from the 5 sigma CO orbital to iron, and back-bonding from the iron to the 2 pi orbital of CO. It follows from the results that none of the studied distortions can explain, by itself, the wide variation of the C-O vibrational frequency in the experimentally studied model compounds and heme proteins. To study the dependence of the properties of the FeCO unit on the presence of charged groups in the heme environment, the latter are simulated by the homogeneous electric field and point charges of different magnitude and location. The results show that charged groups can strongly affect the strength of the C-O bond and its vibrational frequency. It is found that the charges located on the distal side of the heme plane can affect the Fe-C and C-O bond indexes (and, consequently, the Fe-C and C-O vibrational frequencies), both in the same and in opposite directions, depending on their position. The theoretical results allow us to understand the peculiarities of the effect of charged groups on the properties of the FeCO unit both in heme proteins and in their model compounds.

This article has been cited by other articles:

				B. M. Leu, N. J. Silvernail, M. Z. Zgierski, G. R. A. Wyllie, M. K. Ellison, W. R. Scheidt, J. Zhao, W. Sturhahn, E. E. Alp, and J. T. Sage Quantitative Vibrational Dynamics of Iron in Carbonyl Porphyrins Biophys. J., June 1, 2007; 92(11): 3764 - 3783. [Abstract] [Full Text] [PDF]

				A. D. Kaposi, J. M. Vanderkooi, and S. S. Stavrov Infrared Absorption Study of the Heme Pocket Dynamics of Carbonmonoxyheme Proteins Biophys. J., December 1, 2006; 91(11): 4191 - 4200. [Abstract] [Full Text] [PDF]

				T. K. Das, S. Dewilde, J. M. Friedman, L. Moens, and D. L. Rousseau Multiple Active Site Conformers in the Carbon Monoxide Complexes of Trematode Hemoglobins J. Biol. Chem., April 28, 2006; 281(17): 11471 - 11479. [Abstract] [Full Text] [PDF]

				H. Lehle, J. M. Kriegl, K. Nienhaus, P. Deng, S. Fengler, and G. U. Nienhaus Probing Electric Fields in Protein Cavities by Using the Vibrational Stark Effect of Carbon Monoxide Biophys. J., March 1, 2005; 88(3): 1978 - 1990. [Abstract] [Full Text] [PDF]

				A. Sato, Y. Sasakura, S. Sugiyama, I. Sagami, T. Shimizu, Y. Mizutani, and T. Kitagawa Stationary and Time-resolved Resonance Raman Spectra of His77 and Met95 Mutants of the Isolated Heme Domain of a Direct Oxygen Sensor from Escherichia coli J. Biol. Chem., August 30, 2002; 277(36): 32650 - 32658. [Abstract] [Full Text] [PDF]

				S.-R. Yeh, M. Couture, Y. Ouellet, M. Guertin, and D. L. Rousseau A Cooperative Oxygen Binding Hemoglobin from Mycobacterium tuberculosis. STABILIZATION OF HEME LIGANDS BY A DISTAL TYROSINE RESIDUE J. Biol. Chem., January 21, 2000; 275(3): 1679 - 1684. [Abstract] [Full Text] [PDF]

				T. K. Das, H. C. Lee, S. M. G. Duff, R. D. Hill, J. Peisach, D. L. Rousseau, B. A. Wittenberg, and J. B. Wittenberg The Heme Environment in Barley Hemoglobin J. Biol. Chem., February 12, 1999; 274(7): 4207 - 4212. [Abstract] [Full Text] [PDF]

				M. Karavitis, C. Fronticelli, W. S. Brinigar, G. B. Vasquez, V. Militello, M. Leone, and A. Cupane Properties of Human Hemoglobins with Increased Polarity in the alpha - or beta -Heme Pocket. CARBONMONOXY DERIVATIVES J. Biol. Chem., September 11, 1998; 273(37): 23740 - 23749. [Abstract] [Full Text] [PDF]

				S. Franzen and S. G. Boxer On the Origin of Heme Absorption Band Shifts and Associated Protein Structural Relaxation in Myoglobin following Flash Photolysis J. Biol. Chem., April 11, 1997; 272(15): 9655 - 9660. [Abstract] [Full Text] [PDF]