How phage fd uses prolyl isomerization and partial unfolding to activate its gene-3-protein for infection
Zusammenfassung der Projektergebnisse
The infection of E. coli by filamentous phages is a two-step process mediated by the gene-3-protein (G3P) located at the tip of the phage. First, G3P attaches to the tip of E. coli pili before reaching the ultimate phage receptor TolA at the cell surface. Analyses of this infection process by biochemical and biophysical experiments revealed different molecular mechanisms for phages fd, IF1, and IKe. The G3P of all studied phages comprise three domains, one for anchoring in the phage coat, a second for pilus binding and a third for binding to the E. coli receptor. In terms of thermodynamic stability of cis-proline containing proteins, one proline residue in the isolated pilus binding domain of phage fd was systematically analyzed by combining mutagenesis and protein folding experiments. About 10 kJ/mol gained from conformational folding of the protein domain is required to keep the majority of protein molecules in the cis-proline state. In the G3P of phage fd, the receptor binding domain is blocked by tight binding of the pilus binding domain rendering the phages in the latent, non-infectious form. Pilus binding opens this domain pair and a single proline residue functions as a molecular times by preventing re-association for an extended amount of time to facilitate receptor binding. A net of hydrogen binds communicate the status of this proline residue to the remote domain interface. The pilus and receptor binding domains in phage IF1 are independent units and therefore the receptor binding domain is not buried. IF1 therefore developed an different mechanism for a robust infectivity by individually stabilizing each of the domains. A surprising result was obtained for phage IKe. Although both domains are also as independent as found in phage IF1, but the rank order of pilus binding and TolA receptor binding are reversed finally leading to a much lower infectivity. One of our publications was paper of the week in the Journal of Biological Chemistry (May 3, 2013).
Projektbezogene Publikationen (Auswahl)
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A remote prolyl isomerization controls domain assembly via a hydrogen bonding network. Proc. Nat. Acad Sci. USA 106 (2009) 12335-12340
U. Weininger, R. P. Jakob, B. Eckert, K. Schweimer, F. X. Schmid & J. Balbach
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Chaperone domains convert prolyl isomerases into generic catalysts of protein folding. Proc Natl Acad Sci USA 106 (2009) 20282-20287
R. P. Jakob, G. Zoldák G, T. Aumüller, F. X. Schmid
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Molecular determinants of a native-state prolyl isomerization. J. Mol. Biol. 387 (2009) 1017-1031
R. P. Jakob & F. X. Schmid
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Elimination of a cis-proline-containing loop and turn optimization stabilizes a protein and accelerates its folding. J. Mol. Biol. 399 (2010) 331-346
R. P. Jakob, B. K. Zierer, U. Weininger, S. D. Hofmann, S. H. Lorenz, J. Balbach, H. Dobbek & F. X. Schmid
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Reprogramming the infection mechanism of a filamentous phage. Mol Microbiol 80 (2011) 827-3
S. H. Lorenz & F. X. Schmid
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The Filamentous Phages fd and IF1 Use Different Mechanisms to Infect Escherichia coli. J. Mol. Biol. 405 (2011) 989-1003
S. H. Lorenz, R. P. Jakob, U. Weininger, J. Balbach, H. Dobbek & F. X. Schmid
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Structural and energetic basis of infection by the filamentous bacteriophage IKe. Mol Microbiol 84 (2012) 1124-1138
R. P. Jakob, A.-J. Geitner, U. Weininger, J. Balbach, H. Dobbek & F. X. Schmid
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Initiation of phage infection by partial unfolding and prolyl isomerization J. Biol. Chem. 288 (2013) 12979-12991
S. Hoffmann-Thoms, U. Weininger, B. Eckert, R. P. Jakob, J. R. Koch, J. Balbach & F. X. Schmid
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Energetic Communication between Functional Sites of the Gene-3-Protein during Infection by Phage fd. J. Mol. Biol. 426 (2014) 1711–1722
S. Hoffmann-Thoms, R. P. Jakob RP & Schmid FX.
