Abstract

A number of metalloproteins containing nonheme-iron centers have been investigated in the past decade. This class includes catechol 2,3-dioxygenase (2,3-CTD), purple acid phosphatase, methane monooxygenase, and stearoyl desaturase. We have obtained and analyzed data for 2,3-CTD and its substrate complexes. A 5-coordinate iron site with an average Fe-ligand distance of 2.09 is found in the isolated protein; catechol binding elicits a new short bond at 1.93, which is proposed to be the oxygen from the deprotonated hydroxyl group of the coordinated catecholate monoanion. This paper is published. We have collected and analyzed data on an Fe (III) Zn(II) derivative of the purple acid phosphatase from porcine uterus which allows us to look at the Fe(III) and the Zn (II) sites separately. In the phosphate complex of this derivative, the observation of Fe-Zn and M-P (M=3D Fe, Zn) distances of 3.3 and 3.2, respectively, indicates an FeZn(OR)2 core structure and phosphate is proposed to bind to the metal center in a bridging mode. This paper is submitted. Data was also collected on methane monooxygenase hydroxylase (MMOH) and stearoyl ACP = C69 desaturase, the newest member of this class of proteins. XAS analysis of MMOH suggests the presence of two Fe-Fe distances of about 3 and 3.4, which are proposed to reflect two populations of MMOH molecules with either a bis(m-hydroxo)(m-carboxylato)-or a (m-hydroxox)(m-carboxylato)diiron(III) core structure, respectively. The paper is in press. With the crystallographic data available for hemerythrin, ribonucleotide reductase and the hydroxylase component of methane monooxygenase, kidney bean phosphatase, and EXAFS data for the other proteins, we will be able to identify the common structural features that make up these dimetallic sites within this class and to discern the variations in structure that control mechanism and function. We have also examined the EXAFS of model complexes related to intermediates of these iron proteins; these results are published. Data was also taken and analyzed on copper model complexes modeling the copper dioxygen chemistry in metalloproteins, and this paper is published. In two cases, the EXAFS analysis has been crucial for the structure determination of these unstable model complexes.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR001633-14
Application #
5223477
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
14
Fiscal Year
1996
Total Cost
Indirect Cost

  Publications

Vongsvivut, Jitraporn; Fernandez, Jason; Ekgasit, Sanong et al. (2004) Characterization of supported cylinder-planar germanium waveguide sensors with synchrotron infrared radiation. Appl Spectrosc 58:143-51
Masip, Lluis; Pan, Jonathan L; Haldar, Suranjana et al. (2004) An engineered pathway for the formation of protein disulfide bonds. Science 303:1185-9
Huang, Raymond Y; Miller, Lisa M; Carlson, Cathy S et al. (2003) In situ chemistry of osteoporosis revealed by synchrotron infrared microspectroscopy. Bone 33:514-21
Rashidzadeh, Hassan; Khrapunov, Sergei; Chance, Mark R et al. (2003) Solution structure and interdomain interactions of the Saccharomyces cerevisiae ""TATA binding protein"" (TBP) probed by radiolytic protein footprinting. Biochemistry 42:3655-65
Uchida, Takeshi; Takamoto, Keiji; He, Qin et al. (2003) Multiple monovalent ion-dependent pathways for the folding of the L-21 Tetrahymena thermophila ribozyme. J Mol Biol 328:463-78
Taylor, Colleen M; Watton, Stephen P; Bryngelson, Peter A et al. (2003) Inner-sphere complexation of cobalt(II) 2,9-dimethyl-1,10-phenanthroline ([Co(neo)]2+) with commercial and sol-gel derived silica gel surfaces. Inorg Chem 42:312-20
Dewan, John C; Feeling-Taylor, Angela; Puius, Yoram A et al. (2002) Structure of mutant human carbonmonoxyhemoglobin C (betaE6K) at 2.0 A resolution. Acta Crystallogr D Biol Crystallogr 58:2038-42
Kiselar, J G; Maleknia, S D; Sullivan, M et al. (2002) Hydroxyl radical probe of protein surfaces using synchrotron X-ray radiolysis and mass spectrometry. Int J Radiat Biol 78:101-14
Swisher, Jennifer F; Su, Linhui J; Brenowitz, Michael et al. (2002) Productive folding to the native state by a group II intron ribozyme. J Mol Biol 315:297-310
Dhavan, Gauri M; Crothers, Donald M; Chance, Mark R et al. (2002) Concerted binding and bending of DNA by Escherichia coli integration host factor. J Mol Biol 315:1027-37

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