Urease-associated heat shock protein of Helicobacter pylori.
Helicobacter pylori urease is an extracellular, cell-bound enzyme with a molecular weight of approximately 600,000 (600K enzyme) comprising six 66K and six 31K subunits. A 62K protein is closely associated with the H. pylori urease, both in crude preparations and after gel filtration; this protein can be removed from the urease by ion-exchange chromatography without inactivating the enzyme. We purified this urease-associated protein and determined its N-terminal amino acid sequence. The sequence is 80% homologous (identical plus conserved amino acid residues) to the Escherichia coli GroEL heat shock protein (HSP), 75% homologous to the human homolog, and 84% homologous to the HSP homolog found in species of Chlamydia. Thus, the 62K urease-associated protein of H. pylori belongs to the HSP60 family of stress proteins known as chaperonins. Evidently this protein, HSP62, participates in the extracellular assembly and/or protection of the urease against inactivation in the hostile environment of the stomach.
Bacterial Enteropathogens Laboratory, Veterans Affairs Medical Center, Houston, Texas.
D J
DJ
Evans
D G
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Evans
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L
Engstrand
D Y
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Graham
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000032:analysis; D018834:Chaperonin 60; D006360:Heat-Shock Proteins / Q000032:analysis* / Q000276:immunology / Q000502:physiology; D016480:Helicobacter pylori / Q000737:chemistry*; D008969:Molecular Sequence Data; D014510:Urease / Q000032:analysis*
D001426:Bacterial Proteins; D018834:Chaperonin 60; D006360:Heat-Shock Proteins; D014510:Urease