Crystal structure of P22 tailspike protein: interdigitated subunits in a thermostable trimer

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Science  15 Jul 1994:
Vol. 265, Issue 5170, pp. 383-386
DOI: 10.1126/science.8023158


The tailspike protein (TSP) of Salmonella typhimurium phage P22 is a part of the apparatus by which the phage attaches to the bacterial host and hydrolyzes the O antigen. It has served as a model system for genetic and biochemical analysis of protein folding. The x-ray structure of a shortened TSP (residues 109 to 666) was determined to a 2.0 angstrom resolution. Each subunit of the homotrimer contains a large parallel beta helix. The interdigitation of the polypeptide chains at the carboxyl termini is important to protrimer formation in the folding pathway and to thermostability of the mature protein.