Throughout my research career my interests have focussed on bacterial nitrogen metabolism and the ways in which bacteria control all aspects of that metabolism in response to the availability of fixed nitrogen. Bacteria can use a wide range of organic and inorganic sources of nitrogen and they must therefore coordinate both the expression of genes and the activities of proteins required for nitrogen metabolism with the availability of nitrogen sources in their environment and with their intracellular nitrogen status (for reviews see: Merrick and Edwards, 1995; Arcondeguy et al, 2001; Huergo et al, 2012).
Over the last decade, the major research in my lab concerned the biology of the ubiquitous ammonium transport (Amt) proteins and of the signal transduction proteins of the PII family. Ammonium transport (Amt) proteins are found in eubacteria, archaebacteria, fungi, plants, and lower animals. Members of the Amt family are also present in higher animals including humans where their homologues are the Rhesus (Rh) proteins. In my laboratory we developed the AmtB protein of Escherichia coli as a model which offers an excellent system to investigate questions of structure, function and signal transduction relating to Amt proteins (Merrick et al., 2006). PII proteins control nitrogen metabolism in prokaryotes and in plant plastids (for a review see: Huergo et al, 2012). These proteins have a remarkable ability to regulate the activities of transcription factors, enzymes and membrane proteins.
Radchenko M. V., Thornton J., Merrick M. (2010)
Control of AmtB-GlnK complex formation by intracellular levels of ATP, ADP and 2-Oxoglutarate
Journal of Biological Chemistry 285 (40) 31037-31045
Truan D., Huergo L. F., Chubatsu L. S., Merrick M., Li X. D., Winkler F. K. (2010)
A new PII protein structure identifies the 2-oxoglutarate binding site.
Journal of Molecular Biology 400 531-539
Huergo L. F., Chandra G., Merrick M. (2013)
P(II) signal transduction proteins: nitrogen regulation and beyond.
FEMS Microbiology Reviews 37 251-283
Huergo L. F., Pedrosa F. O., Muller-Santos M., Chubatsu L. S., Monteiro R. A., Merrick M., Souza E. M. (2012)
PII signal transduction proteins: pivotal players in post-translational control of nitrogenase activity.
Microbiology 158 (Pt 1) 176-190
Pullan S. T., Chandra G., Bibb M. J., Merrick M. (2011)
Genome-wide analysis of the role of GlnR in Streptomyces venezuelae provides new insights into global nitrogen regulation in actinomycetes
BMC Genomics 12 175
Radchenko M., Merrick M. (2011)
The role of effector molecules in signal transduction by Pll proteins
Biochemical Society Transactions 39 (1) 189-194
Rajendran C., Gerhardt E. C. M., Bjelic S., Gasperina A., Scarduelli M., Pedrosa F. O., Chubatsu L. S., Merrick M., Souza E. M., Winkler F. K., Huergo L. F., Li X. D. (2011)
Crystal structure of the GlnZ-DraG complex reveals a different form of PII-target interaction.
Proceedings of the National Academy of Sciences of the United States of America 108 (48) E1254-1263