Brian F. Volkman, Ph.D.
Associate Professor
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Dr. Volkman obtained his Bachelor of Science degree in Chemistry and Physics from Butler University in 1989 and his Doctorate degree from The University of California at Berkeley. The latter was awarded in 1994 for structural studies on proteins involved in bacterial gene regulation using NMR spectroscopy. Dr. Volkman's postdoctoral training was in the Department of Biochemistry at the University of Wisconsin-Madison. In 2000, Dr. Volkman started at the Medical College of Wisconsin where he is Associate Professor in the Biochemistry Department. Dr. Volkman's work focuses on the structural biology of immunological signaling molecules and the use of NMR spectroscopy in structural proteomics. |
Contact Information
Phone: (414) 955-8400
Fax: (414) 955-6510
Email: bvolkman@mcw.edu
Research Interests
We use NMR spectroscopy and a wide range of structural and functional methods to characterize protein complexes of high biomedical significance. NMR is uniquely sensitive to three-dimensional structural arrangements and the fluctuations that proteins and other biomolecules experience as they interact. It is the only approach that can detect and quantify the internal dynamics associated with conformational changes in enzymes and signaling molecules at atomic resolution. We are particularly interested in molecular recognition and conformational changes that govern cell migration, a fundamental process in many biological contexts. All our projects employ the tools of structural biology to characterize novel proteins and signaling complexes and with relevance to human health and disease. In each case, we test our structural models in a functional context, usually by designing mutant proteins to alter biological activity in cellular or animal models for cancer, autoimmune disease or infection by bacterial or viral pathogens, including anthrax and HIV-1. Some of the projects currently funded by NIH grants are highlighted below.
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Chemokine signaling: Chemokines provide many of the directional cues for motile cells in development and adult homeostasis. This family of ~50 secreted proteins and their ~20 target G protein-coupled receptors forms a complex regulatory network that connects the innate and adaptive immune systems, serving as primary mediators of inflammation while also directing the homing and maturation of lymphocytes. We have solved 3D structures for a number of chemokines, and are currently focused on two chemokine signaling systems with unique functional roles in human immunity and disease, stromal cell-derived factor-1 (SDF-1/CXCL12) and lymphotactin/XCL1.
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Lymphotactin (Ltn/XCL1): Lymphotactin (Ltn/XCL1) is a chemokine that recruits T and NK cells and is produced mainly by activated CD8+ T cells and activated NK cells. Like other chemokines, Ltn induces intracellular calcium mobilization and chemotaxis by binding a specific G protein-coupled receptor (GPCR), called XCR1. Ltn, the defining member of the C class of chemokines, undergoes a conformational change that involves the complete restructuring of all stabilizing interactions. Other chemokines are restricted to a single conformation by a pair of conserved disulfide crosslinks, one of which is absent in lymphotactin. This structural interconversion is entirely reversible, and the two-state equilibrium is sensitive to changes in temperature and ionic strength. Read more...
SDF-1/CXCL12: The chemokine stromal cell-derived factor-1 (SDF-1/CXCL12) directs leukocyte migration, stem cell homing and cancer metastasis through activation of CXCR4, which is also a coreceptor for T–tropic HIV-1. Recently, SDF-1 was shown to play a protective role after myocardial infarction, and the protein is a candidate for development of new anti-ischemic compounds. SDF-1 exists in a monomer-dimer equilibrium that shifts toward dimer upon crystallization and in the presence of various binding partners, including an extracellular domain of its receptor CXCR4. Read more...
Phage lysins as novel anti-bacterial agents: Phage lysins as novel anti-bacterial agents ¬– Infection by drug-resistant bacterial human pathogens is a serious concern for healthcare in the U.S. Bacteriophages encode lysozyme-like enzymes called lysins that hydrolyze cell wall peptidoglycan and rapidly induce bacterial cell lysis. Because phage lysins bind to cell wall structures that are essential for cell viability (usually carbohydrates) bacteria do not develop resistance as easily as with traditional antibiotic drugs. In fact, lysin resistance, though tested extensively, has not been found with any of the currently identified lysins. Enzymes engineered for treatment of bacterial infections are part of a new class of antibiotics known as ‘enzybiotics’. A lysin encoded by gamma phage, PlyG, selectively kills Bacillus anthracis (the bacterial pathogen that causes anthrax) and can inactivate germinating spores in vivo to prevent anthrax infection. Read more...
Structural genomics at MCW – Unprecedented numbers of gene products are now available for study, due to the success of genome sequencing projects. Characterization of the three-dimensional structures of these proteins is an important part of the ongoing revolution in molecular biology, in research areas called proteomics, functional genomics and structural genomics. As a partner in the Center for Eukaryotic Structural Genomics (CESG)[LINK--http://www.uwstructuralgenomics.org/], we develop and apply streamlined methods for (i) high-throughput robotic protein production (ii) acquisition and analysis of protein NMR data and (iii) determination of three-dimensional structures. Using our novel approaches, dozens of isotope-labeled NMR samples can be expressed, purified and screened by 2D HSQC each week. Likewise, we collect a complete NMR structure dataset on cryoprobe-equipped 600 MHz NMR spectrometers in as little as seven days. Automated software speeds the NOE assignment and refinement process so that protein structures up to 25 kDa can be completely solved in just a few weeks. We encourage and assist our colleagues in exploiting these technological advances for the study of their favorite proteins and complexes. Our participation in the CESG is supported by the NIGMS (U54 GM074901). Read more.....
Selected Publications
"Sequential Tyrosine Sulfation of CXCR4 by Tyrosylprotein Sulfotransferases" Seibert, C, Veldkamp, CT, Peterson, FC, Chait, B, Volkman, BF, Sakmar, T, 2008 Oct 28;47(43):11251-62. Epub 2008 Oct 4.
"Structural basis of CXCR4 sulfotyrosine recognition by the chemokine SDF1/CXCL12." Veldkamp, CT, Seibert, C, Peterson, FC, De la Cruz, NB, Haugner, JC, Basnet, H, Sakmar, TP, and Volkman, BF 2008 Sep 16;1(37):ra4.
Heterodimer formation of the myeloid zinc finger 1 SCAN domain and association with promyelocytic leukemia nuclear bodies." Noll L, Peterson FC, Hayes PL, Volkman BF, Sander T Leuk 2008 Oct;32(10):1582-92. Epub 2008 May 9.
"Diversity of polyproline recognition by EVH1 domains." Peterson, FC and Volkman, BF, 2009 Jan 1;14:833-46.
"Altered dimer interface decreases stability in an amyloidogenic protein." E.M. Baden, B.A.L. Owen, F.C. Peterson, B.F. Volkman, M. Ramirez-Alvardo and J.R. Thompson. J. Biol. Chem.
2008 Jun 6;283(23):15853-60. Epub 2008 Apr 8
"Interconversion between two unrelated protein folds in the lymphotactin native states." R.L. Tuinstra, F.C. Peterson, E.S. Elgin and B.F. Volkman. 2008 Apr 1;105(13):5057-62. Epub 2008 Mar 25
"Solution structure of ZNF593 from Homo sapiens." P.L. Hayes, B.L. Lytle, B.F. Volkman and F.C. Peterson. Protein Sci., 17: 571-576 (2008).
"Solution structure of At3g28950 from Arabidopsis thaliana." N.B. De la Cruz, F.C. Peterson and B.F. Volkman. Proteins, 72: 546-555 (2008).
"Structures of proteins of biomedical interest from the Center for Eukaryotic Structural Genomics." G.N. Phillips Jr., B.G. Fox, J.L. Markley, B.F. Volkman, E. Bae, E. Bitto, C.A. Bingman, R.O. Frederick, J.G. McCoy, B.L. Lytle, B.S. Pierce, J. Song and S.N. Twigger. J. Struct. Func. Genomics, 8: 73-84 (2007).
"Solution structure of a membrane-anchored ubiquitin-fold (MUB) protein from Homo sapiens." N.B. De la Cruz, F.C. Peterson, B.L. Lytle, and B.F. Volkman. Protein Sci. 16: 1479-84 (2007).
"An engineered second disulfide bond restricts lymphotactin/XCL1 to a chemokine-like conformation with XCR1 agonist activity." R. Tuinstra, E.S. Elgin, F.C. Peterson and B.F. Volkman. Biochemistry 46 2564-2573 (2007).
"Multiple independent WIP recognition motifs are required for a functional interaction with N-WASP." F.C. Peterson, Q. Deng, M. Zettl, K.E. Prehoda, W.A. Lim, M. Way and B.F. Volkman. J Biol Chem 282 8446-8453 (2007).
"On-column refolding of recombinant chemokines for NMR studies and biological assays." C.T. Veldkamp, F.C. Peterson, P.L. Hayes, J. Mattmiller, J.C. Haugner, N. De la Cruz and B.F. Volkman, Protein Expr Purif 52 202-209 (2007).
"Structural determinants involved in the regulation of CXCL14/BRAK expression by the 26S proteasome." F.C. Peterson, A.G Harder, J.A. Thorpe, B.F. Volkman and S.R. Schwarze. J Mol Biol 363 813-822(2006).
"The first structure of a protein from the SOUL/HBP family: murine p22HBP." J.S. Dias, A.L. Macedo, G.C. Ferreira, F.C. Peterson, B.F. Volkman and B.J. Goodfellow. J Biol Chem 281 10461-73 (2006).
"Solution structure of the MZF1/ZNF42 SCAN domain homodimer." F.C. Peterson, P.L. Hayes, J.K. Waltner, A.K. Heisner, D. R. Jensen, T.L. Sander and B.F. Volkman. J Mol Biol 363 137-47 (2006).
"γ-Glutamylcysteine Synthetase – Glutathione Synthetase: Domain Structure and Identification of Residues Important in Substrate and Glutathione Binding." B.E. Janowiak, M.A. Hayward, F.C. Peterson, B.F. Volkman and O.W. Griffith. Biochemistry 45 10461-73 (2006).
"Solution structure of Arabidopsis thaliana protein At5g39720.1, a member of the AIG2-like protein family." B.L. Lytle, F.C. Peterson, E.M. Tyler, C.L. Newman, D.A. Vinarov, J.L. Markley and B.F. Volkman. Acta Crystallograph Sect F 62 490-3 (2006).
"Recognition of a CXCR4 sulfotyrosine by the chemokine stromal cell-derived factor-1α (SDF-1αCXCL12)." C.T. Veldkamp, C. Seibert, F.C. Peterson, T.P. Sakmar and B.F. Volkman. J Mol Biol 359 1400-9 (2006).
"Structure of the B3 domain from Arabidopsis thaliana protein At1g16640." JK Waltner, F.C. Peterson, B.L. Lytle and B.F. Volkman. Protein Sci 14 2478-83 (2005).
"Solution structure of thioredoxin h1 from Arabidopsis thaliana." F.C. Peterson, B.L. Lytle, E. Tyler, D.A. Vinarov, J.L. Markley and B.F. Volkman. Protein Sci, 14 2195-2200 (2005).
"The monomer-dimer equilibrium of Stromal Cell Derived Factor-1 is altered by pH and phosphate, sulfate, and heparin binding." C.T. Veldkamp, F.C. Peterson, A. Pelzek and B.F. Volkman. Protein Sci, 14 1071-81 (2005).
"Cell-free protein production and labeling protocol for NMR-based structural proteomics." D.A. Vinarov, B.L. Lytle, F.C. Peterson, E. Tyler, B.F. Volkman and J.L Markley. Nat Meth 1 149-153 (2004).
"Solution structure of a ubiquitin-like domain from tubulin-binding cofactor B." B.L. Lytle, F.C. Peterson, S.H. Qiu, M. Luo, Q. Zhao, J.L. Markley and B.F. Volkman. J. Biol. Chem.
"Cdc42 Regulates the Par-6 PDZ Domain Through an Allosteric CRIB-PDZ Transition." F.C. Peterson, R.R. Penkert, B.F. Volkman and K.E. Prehoda. Mol Cell 13 665-676 (2004).
"A glycosaminoglycan recognition element of Lymphotactin essential for in vivo chemokine activity." F.C. Peterson, E.S. Elgin, T.J. Nelson, F. Zhu, T.J. Hoeger, R.J. Linhardt and B.F. Volkman. J Biol Chem 279 12598-12604 (2004).
"A novel zinc-finger is required for Mcm10 homocomplex assembly." C.R. Cook, G. Kung, F.C. Peterson, B.F. Volkman and M. Lei. J. Biol. Chem. 278: 36051-8. (2003).
"Structure of the N-WASP EVH1 Domain-WIP Complex: Insight into the Molecular Basis of Wiskott-Aldrich Syndrome." B.F. Volkman, K.E. Prehoda, J.A. Scott, F.C. Peterson and W.A. Lim. Cell, 111: 565-576. (2002).
"Conformational rearrangement in the C chemokine lymphotactin."
E.S. Kuloglu, C.D. Pauza, J.L. Markley and B.F. Volkman. J. Biol. Chem, 277, 17863-17870 (2002).
"Staphylococcal superantigens induce lymphotactin production by human CD4+ and CD8+ T cells." I. Tikhonov, M. Kitabwalla, M. Wallace, M. Malkovsky, B.F. Volkman and C.D. Pauza. Cytokine, 16: 73-78. (2001).
"Monomeric Solution Structure of the Prototypical 'C' Chemokine Lymphotactin." E.S. Kuloglu, D.R. McCaslin, M. Kitabwalla, C.D. Pauza, J.L. Markley and B.F. Volkman. Biochemistry 40: 12486-12496. (2001).
"Solution structure of a type I dockerin domain, a novel prokaryotic, extracellular calcium-binding domain." B.L. Lytle, B.F. Volkman, W.M. Westler, and J.H.D. Wu. J. Mol. Biol. 307: 745-753. (2001).
"Two-state allosteric behavior in a single domain signaling protein."B.F. Volkman, D. Lipson, D.E. Wemmer, and D. Kern. Science 291: 2429-2433. (2001).
"Structure of a transiently phosphorylated switch in bacterial signal transduction." D. Kern, B.F. Volkman, P. Luginbuhl, M.J. Nohaile, S. Kustu and D.E. Wemmer. Nature, 402: 894-898. (1999).