3FY3

Crystal structure of truncated hemolysin A from P. mirabilis

Summary for 3FY3

• Entry DOI: 10.2210/pdb3fy3/pdb
• Descriptor: Hemolysin (1 entity in total)
• Functional Keywords: beta helix, hemolysin, solenoid, two partner secretion, cell membrane, cell outer membrane, cytolysis, hemolysis, membrane, toxin
• Biological source: Proteus mirabilis
• Cellular location: Cell outer membrane: P16466
• Total number of polymer chains: 1
• Total formula weight: 24650.24

Authors

Weaver, T.M.,Thompson, J.R.,Bailey, L.J.,Wawrzyn, G.T.,Hocking, J.M.,Howard, D.R. (deposition date: 2009-01-21, release date: 2009-06-02, Last modification date: 2023-09-06)

Primary citation

Weaver, T.M.,Hocking, J.M.,Bailey, L.J.,Wawrzyn, G.T.,Howard, D.R.,Sikkink, L.A.,Ramirez-Alvarado, M.,Thompson, J.R.
Structural and functional studies of truncated hemolysin A from Proteus mirabilis.
J.Biol.Chem., 284:22297-22309, 2009

PubMed Abstract: In this study we analyzed the structure and function of a truncated form of hemolysin A (HpmA265) from Proteus mirabilis using a series of functional and structural studies. Hemolysin A belongs to the two-partner secretion pathway. The two-partner secretion pathway has been identified as the most common protein secretion pathway among Gram-negative bacteria. Currently, the mechanism of action for the two-partner hemolysin members is not fully understood. In this study, hemolysis experiments revealed a unidirectional, cooperative, biphasic activity profile after full-length, inactive hemolysin A was seeded with truncated hemolysin A. We also solved the first x-ray structure of a TpsA hemolysin. The truncated hemolysin A formed a right-handed parallel beta-helix with three adjoining segments of anti-parallel beta-sheet. A CXXC disulfide bond, four buried solvent molecules, and a carboxyamide ladder were all located at the third complete beta-helix coil. Replacement of the CXXC motif led to decreased activity and stability according to hemolysis and CD studies. Furthermore, the crystal structure revealed a sterically compatible, dry dimeric interface formed via anti-parallel beta-sheet interactions between neighboring beta-helix monomers. Laser scanning confocal microscopy further supported the unidirectional interconversion of full-length hemolysin A. From these results, a model has been proposed, where cooperative, beta-strand interactions between HpmA265 and neighboring full-length hemolysin A molecules, facilitated in part by the highly conserved CXXC pattern, account for the template-assisted hemolysis.

PubMed: 19494116
DOI: 10.1074/jbc.M109.014431

Experimental method

X-RAY DIFFRACTION (1.8 Å)