Bacterial microcompartments are large subcellular structures composed of metabolic enzymes encapsulated within a protein shell built from multiple subunits. They are widespread among bacteria, functionally diverse, linked to pathogenesis, have a number of important potential biomedical applications, and appear to incorporate unique mechanistic and structural principles. Their function is to sequester and regulate the production of toxic or volatile intermediates found in certain metabolic pathways. However, little is known about how this is occurs at the mechanistic level. The long-term goal of the proposed research is to elucidate the molecular principles and to build up a 3-dimensional structure of the microcompartments involved in 1,2-propanediol degradation by Salmonella. The Salmonella system is unmatched with regard to the knowledge and tools available for mechanistic studies of microcompartments. The proposed studies combine genetic, biophysical, and structural methods to elucidate the cellular function of the Salmonella Pdu microcompartment at a mechanistic level.
Three specific aims are proposed: 1. Determine the role of terminal helixes and other mechanisms for targeting proteins to the lumen of the Pdu microcompartment;2. Determine the role of pores and cofactor recycling in supplying the lumen enzymes of the Pdu microcompartment with required substrates and cofactors;and 3. Elucidate the higher order structure and assembly of the Pdu microcompartment. Structures will be investigated and analyzed by x-ray crystallography, biophysical, and computational methods. Protein-protein binding studies will include his-tag pulldowns, biophysical methods, and crystallography. Functional and mechanistic insights will be derived from structure-guided mutagenesis in conjunction with genetic and biochemical studies. Completion of the proposed investigations will elucidate the mechanistic and structural principles of the Salmonella pdu microcompartment. This will provide general insights into bacterial microcompartments. Since bacterial microcompartments play critical metabolic roles in many microbes, including several human pathogens, the proposed studies may ultimately lead to new opportunities for interfering with pathogenic processes.

Public Health Relevance

An improved understanding of bacterial microcompartments, which are found in many human pathogens, may ultimately lead to new opportunities for interfering with pathogenic processes, and may also provide a basis for the rational design of synthetic protein cages for use in the production of pharmaceuticals or as drug delivery vehicles

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Prokaryotic Cell and Molecular Biology Study Section (PCMB)
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Alexander, William A
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Iowa State University
Schools of Earth Sciences/Natur
United States
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Sinha, Sharmistha; Cheng, Shouqiang; Sung, Yea Won et al. (2014) Alanine scanning mutagenesis identifies an asparagine-arginine-lysine triad essential to assembly of the shell of the Pdu microcompartment. J Mol Biol 426:2328-45
Wheatley, Nicole M; Sundberg, Christopher D; Gidaniyan, Soheil D et al. (2014) Structure and identification of a pterin dehydratase-like protein as a ribulose-bisphosphate carboxylase/oxygenase (RuBisCO) assembly factor in the ?-carboxysome. J Biol Chem 289:7973-81
Chowdhury, Chiranjit; Sinha, Sharmistha; Chun, Sunny et al. (2014) Diverse bacterial microcompartment organelles. Microbiol Mol Biol Rev 78:438-68
Thompson, Michael C; Wheatley, Nicole M; Jorda, Julien et al. (2014) Identification of a unique Fe-S cluster binding site in a glycyl-radical type microcompartment shell protein. J Mol Biol 426:3287-304
Jorda, Julien; Lopez, David; Wheatley, Nicole M et al. (2013) Using comparative genomics to uncover new kinds of protein-based metabolic organelles in bacteria. Protein Sci 22:179-95
Wheatley, Nicole M; Gidaniyan, Soheil D; Liu, Yuxi et al. (2013) Bacterial microcompartment shells of diverse functional types possess pentameric vertex proteins. Protein Sci 22:660-5
Sinha, Sharmistha; Cheng, Shouqiang; Fan, Chenguang et al. (2012) The PduM protein is a structural component of the microcompartments involved in coenzyme B(12)-dependent 1,2-propanediol degradation by Salmonella enterica. J Bacteriol 194:1912-8
Yeates, Todd O; Thompson, Michael C; Bobik, Thomas A (2011) The protein shells of bacterial microcompartment organelles. Curr Opin Struct Biol 21:223-31
Cheng, Shouqiang; Sinha, Sharmistha; Fan, Chenguang et al. (2011) Genetic analysis of the protein shell of the microcompartments involved in coenzyme B12-dependent 1,2-propanediol degradation by Salmonella. J Bacteriol 193:1385-92
Fan, Chenguang; Bobik, Thomas A (2011) The N-terminal region of the medium subunit (PduD) packages adenosylcobalamin-dependent diol dehydratase (PduCDE) into the Pdu microcompartment. J Bacteriol 193:5623-8

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