Stephen A. Mills, Ph.D.
Department of Chemistry and Biochemistry
Office: ST 485
Phone: (619) 260-7564
Email: smills@sandiego.edu


Education

B.S. University of Illinois at Urbana-Champaign

M.S. University of California, Berkeley, Advisor: Paul A. Bartlett

Ph.D. University of California, Berkeley, Advisor: Judith P. Klinman

Post-doctoral Fellow, University of California, Berkeley, Advisor: Michael A. Marletta


Curriculum Vitae

 

Courses Taught

Chemistry 301 Organic Chemistry, syllabus

Chemistry 301L Organic Chemistry Lab, syllabus

Chemistry 302 Organic Chemistry II, S07, syllabus

Chemistry 302L Organic Chemistry II Lab, syllabus

Chemistry 331 Biochemistry, syllabus

Chemistry 335 Biochemistry Lab, syllabus

Chemistry 396W Research Methods, syllabus

Chemistry 494 Special Topics: Enzyme Kinetics and Mechanism, syllabus

 

 

Research Interests

The theme of research in our lab is to understand the role of metals in proteins.  We are interested in how the specific metals get into the proteins and why the specific metals are important for the function of the protein.  A primary technique used in our lab is metal substitution.  We then use a variety of techniques to evaluate the effect of different metals on the function of the protein, including enzyme kinetics, gel-shift assays, UV-vis and fluorescence spectroscopy.

 

Specific Systems under study:

Oxygen Activation in the Copper Amine Oxidases (CAOs)        selected references

      The copper amine oxidases (CAOs) are a family of enzymes that oxidize amines using a unique, protein-bound cofactor, trihydroxyphenylalanine quinone (TPQ), and a Cu(II) ion. The cupric ion in these proteins is important for formation of the cofactor and for catalysis once the cofactor is in place. We are examining the role of copper in oxygen activation by these enzymes. More information

 

Ferric Uptake Regulator Fur        selected references

      Fur is an iron-sensing protein that is a key part of bacterial iron metabolism. When there is sufficient iron in the cell, iron binds to Fur and activates the protein to bind DNA. Upon binding DNA, Fur turns off expression of iron importing proteins and prevents the buildup of toxic iron levels. If metals, other than iron, activate Fur for DNA binding, iron import can be turned off when it should remain on and starve the cell for iron. We are examining the affinity and selectivity of Fur from several different bacteria for various metals, including Mn, Fe, Co, and Zn to understand how selective the protein needs to be for proper bacterial growth. By examining Fur homologues, with known primary sequence, from various bacterial species we hope to identify specific amino acids that are important for metal selectivity. More information

 

CoaR A cobalt-specific regulatory protein        selected references

      This is the only known regulatory protein specific for Co in bacteria. It is a part of the vitamin B12 biosynthetic pathway. Little is known about this protein except that it responds to Co and a B12 precursor hydrogenobyrinic acid. We want to examine its selectivity for cobalt over other first-row transition metals and explore the effect of hydrogenobyrinic acid on metal affinity.

 

CAO References

Mills, S., D. Brown, et al. (2012). "Cobalt substitution supports an inner-sphere electron transfer mechanism for oxygen reduction in pea seedling amine oxidase." Journal of Biological Inorganic Chemistry 17(4): 507-515. link

Mills, S. A., Y. Goto, et al. (2002). "Mechanistic comparison of the cobalt-substituted and wild-type copper amine oxidase from Hansenula polymorpha." Biochemistry 41(34): 10577-10584. link

Mure, M., S. A. Mills, et al. (2002). "Catalytic mechanism of the topa quinone containing copper amine oxidases." Biochemistry 41(30): 9269-9278. link

 

Fur References

McHugh, J. P., F. Rodriguez-Quinones, et al. (2003). "Global iron-dependent gene regulation in Escherichia coli. A new mechanism for iron homeostasis." J Biol Chem 278(32): 29478-29486. link

Mills, S. A. and M. A. Marletta (2005). "Metal binding characteristics and role of iron oxidation in the ferric uptake regulator from Escherichia coli." Biochemistry 44(41): 13553-13559. link

Pohl, E., J. C. Haller, et al. (2003). "Architecture of a protein central to iron homeostasis: crystal structure and spectroscopic analysis of the ferric uptake regulator." Mol Microbiol 47(4): 903-915. link

 

CoaR References

Rutherford, J. C., J. S. Cavet, et al. (1999). "Cobalt-dependent transcriptional switching by a dual-effector MerR-like protein regulates a cobalt-exporting variant CPx-type ATPase." J Biol Chem 274(36): 25827-25832. link

Scott, A. I. (2003). "Discovering nature's diverse pathways to vitamin B12: a 35-year odyssey." J Org Chem 68(7): 2529-2539. link

Tottey, S., D. R. Harvie, et al. (2005). "Understanding how cells allocate metals using metal sensors and metallochaperones." Acc Chem Res 38(10): 775-783. link