J.B. Alexander (Sandy) Ross

J.B. Alexander (Sandy) Ross

Professor of Chemistry and Biochemistry

Office: Chem 013A
Email: sandy.ross@umontana.edu
Fax: 406-243-4227


BIOC 581  Physical Biochemistry

CHMY 302e

Personal Summary

J.B. Alexander (Sandy) Ross joined the University of Montana in 2001 as Professor of Chemistry and Biochemistry and Director of the BioSpectroscopy Core Research Laboratory. Sandy became Associate Dean of the Graduate School in 2010 and Dean in 2012. Previously, he was Professor of Biochemistry and Molecular Biology and Co-Director of the Biophysics, Structural Biology, and Biomathematics Training Program at Mount Sinai School of Medicine in New York.

Sandy earned his Ph.D. at the University of Washington in 1976 under the joint supervision of D.A. Deranleau and D.C. Teller. He carried out postdoctoral research under the direction of A.L. Kwiram at the University of Washington, L. Brand at The Johns Hopkins University, and P.H. Petra at the University of Washington. He has been a Visiting Professor at the University of Parma, Italy, and a Visiting Scientist at the National Synchrotron Light Source at Brookhaven National Laboratory.

Sandy is a physical biochemist specializing in time-resolved excited-state spectroscopy and single-molecule experiments. He is an investigator in the Center for Biomolecular Structure and Dynamics and the Center for Structural and Functional Neuroscience and also past Director of the Sloan Indigenous Graduate Partnership at the University of Montana.


B.A.: Antioch College, Yellow Springs (1970)

Ph.D.: University of Washington, Seattle (1976)

Post-Doctoral: University of Washington, Seattle (1976-1978, 1980-1982); The Johns Hopkins University (1978-1980)

Research Interests

Macromolecular Interactions and Dynamics

The goal of our research is to understand how conformational dynamics and interactions of biological molecules regulate function.  Our approach is to use a combination of experimental and computational biophysical methods: we specialize in time-resolved and single-molecule fluorescence spectroscopies; and we collaborate with other groups that specialize in X-ray crystallography, NMR, analytical ultracentrifugation, inorganic chemistry and computational chemistry.  Current research interests include:

Novel Probes for Studying Submicrosecond-to-Microsecond Dynamics: In contrast to fluorescence, which occurs in the time range of ps to tens-of-ns, phosphorescence (at ambient temperatures) occurs in sub-ms to ms. Thus, fluorescence lifetime measurements can provide information about local (specific-site) motions (ps to a few ns) and global motions of macromolecules with molecular weights up to 100 kDa  (~50 ns). To facilitate study the dynamics of larger macromolecules and assemblies that are slower and occur in the 100-ns to 10-ms time-range, in collaboration with the Rosenberg group (NSF CHE-1049569), we have been developing luminescent probes based on organo-metal complexes (metal-ligand complexes) that have lifetimes spanning this time-range and that have high quantum yields and polarized emission.

Membrane-Protein Interactions and dynamics: We are using time-resolved fluorescence microscopy and single-molecule fluorescence spectroscopy to study the conformational dynamics and ligand interactions of membrane proteins incorporated in nanodiscs.  Nanodiscs, largely developed by Sligar and collaborators at the University of Illinois, are mono-disperse, aqueous-soluble assemblies of nm-scale, protein-belted, phospholipid bilayers.  The belt proteins are recombinant constructs based on high-density apolipoprotein A1. The easily controlled lipid composition and stable properties of nanodiscs make them particularly useful as platforms for biophysical study of membrane proteins.

Structural dynamics and enzyme catalysis: G proteins. Correlated motions ranging in time scales from picoseconds to microseconds have been shown to be critical in overcoming activation energy barriers to substrate binding and active site pre-organization for catalysis in enzymes that have turnover rates in the microsecond to millisecond range.  A crucial step in activation of G proteins is exchange of GDP with GTP, which is mediated by guanine nucleotide exchange factors. In collaboration with the Sprang group (R01 GM105993), we are using single-molecule fluorescence spectroscopy to understand the role of conformational distributions and dynamic fluctuations in the mechanism of G protein activation.

Field of Study

Physical Biochemistry

Analytical Biochemistry

Biological Fluorescence


Selected Publications

Abbott G, Brooks R, Rosenberg E, Terwilliger M, RossJBA, Ichire OOL: Surface-Bound Ruthenium Diimine Organometallic Complexes: Excited-State Properties. Organometallics, 33:2467-2478, 2014. (DOI: 10.1021/om401153x)

Sharmin A, Salassa L, Rosenberg E, Ross JBA, Abbott G, Black LA, Terwilliger M, Brooks R: Photophysical Studies of Bioconjugated Ruthenium Metal-Ligand Complexes Incorporated in Phospholipid Membrane Bilayers. Inorg Chem, 52:10835–10845, 2013. (DOI: 10.1021/ic400706u)

Manhat BA, Brown AL, Black LA, Ross JBA, Fichter K, Vu T, Richman E, Goforth AM: One-step Melt Synthesis of Water Soluble, Photoluminescent, Surface-Oxidized Silicon Nanoparticles for Cellular Imaging Applications. Chem Mater, 23:2407-2418, 2011. (DOI: 10.1021/cm200270d)

Wang H, Lu M, Tang M-S, Van Houten B, Ross JBA, Le XC: DNA Wrapping on UvrB, Mediated by UvrA, is an Early Event in the Damage Recognition Pathway during E. coli Nucleotide Excision Repair. Proc Natl Acad Sci USA, 106:12849-12854, 2009. (DOI:10.1073/pnas.0902281106)

Sharmin A, Darlington RC, Hardcastle KI, Ravera M, Rosenberg E, Ross JBA: Tuning Photophysical Properties with Ancillary Ligands in Ru(II) Mono-Diimine Complexes. J Organometallic Chem, 694:988-1000, 2009. (DOI: 10.1016/ j.bpj.2008.10.018)

Minazzo A, Darlington RC, Ross JBA: Loop Dynamics of the Extracellular Domain of Human Tissue Factor and Activation of Factor VIIa.  Biophysical J, 96:681-692, 2009. (DOI: 10.1016/ j.bpj.2008.10.018)

Sharmin A, Minazzo A, Salassa L, Rosenberg E, Ross JBA, Shariff SE, Hardcastle KI: Synthesis, Structure, Photophysical and Electrochemical Behavior of 2-amino-Anthracene Triosmium Clusters. Inorg Chim Acta 361:1624-1633, 2008. (DOI: 10.1016/j.ica.2007.03.059)

Garino C, Gobetto R, Nervi C, Salassa L, Rosenberg E, Ross JBA, Chu X, Hardcastle KI, Sabatini C: Spectroscopic and Computational Studies of a Ru(II)Terpyridine Complex: The Importance of Weak Intermolecular Forces to Photophysical Properties. Inorg Chem 46:8752-8762, 2007. (DOI: 10.1021/ic7010343)

Senear DF, Tretyachenko-Ladokhina V, Opel ML, Aeling KA, Hatfield GW, Franklin LM, Darlington RC, Ross JBA: Pressure Dissociation of Integration Host Factor-DNA Complexes Reveals Flexibility-Dependent Structural Variation at the Protein-DNA Interface. Nucleic Acids Research 35:1761-1772, 2007. (DOI:10.1093/nar/gkl1122)

       For a full list of publications, please view Ross Publications


A.P. Sloan Mentor of the Year (Compact for Faculty Diversity Institute, 2010)

Teaching Experience

Biochemistry and physical biochemistry since 1982

Professional Experience

  • Visiting Scientist:

National Synchrotron Light Source, Brookhaven National Laboratory

University of Parma

University of Torino

  • Consulting:

Fluorescence Innovations - time-resolved fluorescence

Quantum Northwest - fluorescence instrumentation

Darby & Darby - intellectual property

Fluorescence Unlimited - time-resolved fluorescence in clinical chemistry

  • Executive Editor, Analytical Biochemistry
  • Associate Editor, Cell Biochemistry and Biophysics


American Chemical Society

Biophysical Society

Sigma Xi