Structure of the PduU Shell Protein from the Pdu Microcompartment of Salmonella

• Published in: Structure (London) Vol. 16; no. 9; pp. 1324 - 1332
• Main Authors: Crowley, Christopher S., Sawaya, Michael R., Bobik, Thomas A., Yeates, Todd O.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 10.09.2008; Elsevier
• Subjects: Amino Acid Sequence; Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Bacterial Proteins - physiology; Cell Compartmentation - physiology; Cell Wall - chemistry; Cell Wall - ultrastructure; Crystallography, X-Ray; MICROBIO; Models, Biological; Models, Molecular; Molecular Sequence Data; Porins - chemistry; Porins - metabolism; Porins - physiology; Protein Folding; Protein Structure, Quaternary; Salmonella enterica; Salmonella enterica - chemistry; Salmonella enterica - metabolism; Salmonella enterica - ultrastructure; Sequence Homology, Amino Acid; MICROBIO
• ISSN: 0969-2126; 1878-4186
• DOI: 10.1016/j.str.2008.05.013

The Pdu microcompartment is a proteinaceous, subcellular structure that serves as an organelle for the metabolism of 1,2-propanediol in Salmonella enterica. It encapsulates several related enzymes within a shell composed of a few thousand protein subunits. Recent structural studies on the carboxysome, a related microcompartment involved in CO 2 fixation, have concluded that the major shell proteins from that microcompartment form hexamers that pack into layers comprising the facets of the shell. Here we report the crystal structure of PduU, a protein from the Pdu microcompartment, representing the first structure of a shell protein from a noncarboxysome microcompartment. Though PduU is a hexamer like other characterized shell proteins, it has undergone a circular permutation leading to dramatic differences in the hexamer pore. In view of the hypothesis that microcompartment metabolites diffuse across the outer shell through these pores, the unique structure of PduU suggests the possibility of a special functional role.