Signal transmission through the HtrII transducer alters the interaction of two alpha-helices in the HAMP domain

Journal of Molecular Biology
Keiichi InoueMasahide Terazima

Abstract

A conformational change of the transducer HtrII upon photoexcitation of the associated photoreceptor sensory rhodopsin II (SRII) was investigated by monitoring the kinetics of volume changes and the diffusion coefficient (D) of the complex during the photochemical reaction cycle. To localize the region of the transducer responsible, we truncated it at various positions in the cytoplasmic HAMP (histidine kinases, adenylyl cyclases, methyl-accepting chemotaxis proteins, and phosphatases) domain. The truncations do not alter receptor binding, which is dependent primarily on membrane-embedded domain interactions. We found that the light-induced reduction in D occurs in transducers of lengths 120 and 157 residues (Tr120 and Tr157), which are both predicted to contain a HAMP domain consisting of two amphipathic alpha-helices (AS-1 and AS-2). In contrast, the change in D was abolished in a transducer of 114 amino acid residues (Tr114), which lacks a distal portion of the second alpha-helix AS-2. The volume changes in SRII-Tr114 are comparable in amplitude and kinetics with those in SRII-Tr120 and SRII-Tr157, confirming the integrity of the complex, which was previously concluded from the similar SRII binding affinity and similar block...Continue Reading

References

Oct 10, 2001·Journal of Bacteriology·K H JungJ L Spudich
Sep 13, 2003·Science·Shannon M HarperKevin H Gardner
Sep 30, 2004·Biophysical Journal·Keiichi InoueMasahide Terazima
Jun 14, 2005·The Journal of Biological Chemistry·Vladislav B BergoJohn L Spudich
Feb 3, 2006·Nature·Rouslan MoukhametzianovValentin I Gordeliy
Feb 28, 2006·Biophysical Journal·Javaid Shahbaz KhanMasahide Terazima
Jul 21, 2006·The Journal of Physical Chemistry. B·Keiichi InoueMasahide Terazima
Aug 29, 2006·Biophysical Journal·Takeshi EitokuMasahide Terazima
Sep 29, 2006·Trends in Microbiology·John L Spudich
Feb 6, 2007·Journal of Molecular Biology·Yusuke NakasoneMasahide Terazima

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Citations

Apr 19, 2012·The Journal of Biological Chemistry·Jihong WangJohn L Spudich
May 6, 2009·Biophysical Journal·Keiichi InoueMasahide Terazima
Aug 10, 2010·Annual Review of Microbiology·John S Parkinson
Apr 1, 2011·The Journal of Physical Chemistry. B·Keiichi InoueHideki Kandori

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