Shalley Kudalkar

Shalley joined the Goodwin laboratory in June 2008.  Her project had two major components, each dedicated to one of the extended interhelical loops unique to KatG.  The first is to determine the role of Large Loop 2 (LL2) in giving catalase-peroxidases their striking bifunctional capabilities.  Building on Yongjiang Li's observation that removal of the entire loop leaves KatG peroxidase activity comparable to wild type.  However, there is little if any catalase activity.  Prior to Shalley's work, the mechanism by which this structure specifically supported catalase activity was not known.  Shalley produced a series of KatG variants by site-directed and deletion mutagenesis that specifically targeted the apex of LL2 and found that interactions between LL2 and the enzyme's C-terminal domain were essential for controlling the active site heme coordination environment and H-bonded interactions.  Dr. Kudalkar also evaluated a series of deletion variants targeting Large Loop 1.  Her stopped-flow evaluation of those variants demonstrated that an appropriate deletion not only abrogated catalase activity, but also facilitated electron transfer from exogenous electron donors to the enzyme's heme center.  The net result was a KatG with peroxidase activity ten fold greater than other catalase-negative variants (e.g., Y226F KatG) and rivaling that of the peroxidase gold-standard, horseradish peroxidase.  In December 2011, Shalley successfully defended her dissertation.  It is entitled Roles of large loops in catalytic versatility of catalase-peroxidases: Significance of peripheral structures in improvising enzyme functions.  Dr. Kudalkar engaged in postdoctoral studies at the Vanderbilt University School of Medicine under the direction of Dr. Larry Marnett, and she is now living in Connecticut.

Publications and Abstracts

Kudalkar, S.N., Njuma, O.J., Li, Y., Muldowney, M., Fuanta, N.R., and Goodwin, D.C. 2015.  "A role for catalase-peroxidase large loop 2 revealed by deletion mutagenesis: Control of active site water and ferric enzyme reactivity" Biochemistry 54, 1648 - 1662.

Kudalkar, S.N., Campbell, R.A., Li, Y., Varnado, C.L., Prescott, C., and Goodwin D.C.  2012.  Enhancing the peroxidatic activity of KatG by deletion mutagenesis" J. Inorg. Biochem. 116, 106 - 115.

Kudalkar, S. N., and Goodwin, D. C.  2011.  Tracing the Impact of a Unique Loop in Catalase-peroxidase Catalysis.  Annual Meeting of the American Society for Biochemistry and Molecular Biology, Washington, D. C.

Kudalkar, S. N., and Goodwin, D. C.  2011. Dependence of catalytic ability of catalase-peroxidase on intersubunit interactions.  Annual Meeting of the American Society for Biochemistry and Molecular Biology, Washington, D. C.

Kudalkar, S. N., and Goodwin, D. C., 2011.  Effects of progressive deletion of a unique loop on structure and function of catalase-peroxidases.  Second Southeast Enzymes Conference, Atlanta, GA.

Kudalkar, S. N., and Goodwin, D. C.  2010.  Impact of intersubunit interactions on catalytic versatility of catalase-peroxidases.  First Southeast Enzyme Conference, Atlanta, GA.

Goodwin, D.C., Li, Y, Kudalkar, S., Campbell, R., and Prescott, C. 2009.  Roles of insertional sequences in commandeering an existing enzyme framework for new catalytic function:  A case study in catalase-peroxidases.  Gordon Conference:  Enzymes, Coenzymes, and Metabolic Pathways, Waterville Valley, NH.