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Palaniappa Arjunan, PhD

Research Instructor
VA Medical Center University Drive C
Pittsburgh, PA 15240
Phone: 412-688-6000
Fax: 412-688-6945


BSc (Chemistry), Madurai University, Madurai, India, 1977
MSc (Chemistry), Madurai University, Madurai, India, 1979
PhD (Organic Chemistry and Crystallography), Indian Institute of Science, Bangalore, India, 1985


Headshot of Palaniappa Arjunan, PhD


Research Areas

Dr. Arjunan determines the structure of macromolecules of biological interest, and then analyses structure-function relationships. He primarily uses X-ray crystallography to accomplish this.


Dr. Arjunan's current research includes the high resolution three-dimensional structure determination of thiamin diphosphate(ThDP)-dependent enzymes, the yeast pyruvate decarboxylase (PDC) and pyruvate dehydrogenase multienzyme complex (PDHc) from Escherichia coli. The refined structure is then used to address long-standing issues regarding the structure and function of thiamin diphosphate-dependent enzymes. The structure determination also includes the structure of PDHc E1 in complex with a covalently bound reaction intermediate analogue. Other interests are: a) the crystal structural analysis of native and mutant ThDP-dependent enzymes, either alone or in complexes with substrates, inhibitors, activators or with other related enzymes and b) development of techniques for the determination and analysis of macromolecular crystal structure.

Journal Articles

Nemeria N, P Arjunan, K Chandrasekhar, M Mossad, K Tittmann, W Furey and F Jordan.  Communication between thiamin cofactors in the Escherichia coli pyruvate dehydrogenase complex E1 component active centers.  J Biol Chem 285:11197-11209, 2010.
Jordan F, P Arjunan, S Kale, N Nemeria and W Furey.  Multiple roles of mobile active center loops in the E1 component of the Escherichia coli pyruvate dehydrogenase complex:  Linkage of protein dynamics to catalysis.  J Mol Catal B:  Enzym 61:14-22, 2009.
Kale S, P Arjunan, W Furey and F Jorda. A dynamic loop at the active center of the Escherichia coli pyruvate dehydrogenase complex E1 component modulates substrate utilization and chemical communication with the E2 component, n. J Biol Chem 282:28106-28116, 2007.
Arjunan P, M Sax, A Brunskill, K Chandrasekhar, N Nemeria, S Zhang, F Jordan and W. Furey. A thiamin-bound, pre-decarboxylation reaction intermediate analogue in the pyruvate dehydrogenase E1 subunit induces large-scale disorder-to-order transformations in the enzyme and reveals novel structural features in the covalently bound adduct. J Biol Chem 281:15296-15303, 2006.
Nemeria N, K Tittmann, E Joseph. L Zhou, MB Vazquez-coll, P Arjunan, G Hubner, W Furey and F Jordan. Glutamate 636 of the Escherichia Coli Pyruvate dehydrogenase-E1 participates in active center communication and behaves as an engineered acetolactate synthase with unusual stereoselectivity. J Biol Chem 280:21473-21482, 2005.
Arjunan P, K Chandrasekhar, M Sax, A Brunskill, N Nemeria, F Jordan and W Furey. Structural determinants of enzyme binding affinity: The E1 component of pyruvate dehydrogenase from Escherichia coli in complex with the inhibitor thiamin thiazolone diphosphate. Biochemistry 43:2405-2411, 2004.
Jordan F, N Nemeria, Y Yan, S Zhang, P Arjunan and W Furey. Presence of the 1,4’-imino tautomer of thiamin diphosphate on the E1 subunit of the Escherichia coli pyruvate dehydrogenase complex provides evidence for an acid-base role, in addition to its long-accepted electrophilic role; A coenzyme with dual catalytic machinery. J Am Chem Soc 125:12732-12738, 2003.
Arjunan P, N Nemeria, A Brunskill, K Chandrasekhar, M Sax, Y Yan, F Jordan, JRGuest and W Furey. Structure of the pyruvate dehydrogenase multienzyme complex E1 component from Escherichia coli at 1.85 Å resolution., Biochemistry 41:5213-5221, 2002.