Document Detail

Spectroscopic studies of the AppA BLUF domain from Rhodobacter sphaeroides: addressing movement of tryptophan 104 in the signaling state.
MedLine Citation:
PMID:  19746968     Owner:  NLM     Status:  MEDLINE    
Previous crystallographic studies of the AppA BLUF domain indicated that Trp104 is capable of undertaking alternate conformations depending on the length of the BLUF domain. A BLUF domain containing a C-terminal deletion (AppA1-126) reveals that Trp104 is partially solvent exposed while a BLUF domain containing a slightly longer carboxyl terminal region (AppA17-133) shows that Trp104 is deeply buried. This observation has led to a model proposing that Trp104 moves from a deeply buried position in the dark state to a solvent-exposed position in the light excited state. In this study we investigated whether there is indeed movement of Trp104 upon light excitation using a combination of NMR and absorption spectroscopy, steady-state fluorescence, and acrylamide quenching of tryptophan fluorescence. Our results indicate that AppA17-133 and AppA1-126 contain Trp104 in distinct alternate conformations in solution and that light absorption by the flavin causes partial movement/uncovering of Trp104. However, we conclude that light exposure does not cause dramatic change of Trp104 from "Trp-in" to "Trp-out" conformations (or vice versa) upon light absorption. These results do not support a model of Trp104 movement as a key output signal.
Vladimira Dragnea; Alphonse I Arunkumar; Hua Yuan; David P Giedroc; Carl E Bauer
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  Biochemistry     Volume:  48     ISSN:  1520-4995     ISO Abbreviation:  Biochemistry     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2009-10-20     Completed Date:  2009-11-24     Revised Date:  2014-09-22    
Medline Journal Info:
Nlm Unique ID:  0370623     Medline TA:  Biochemistry     Country:  United States    
Other Details:
Languages:  eng     Pagination:  9969-79     Citation Subset:  IM    
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MeSH Terms
Bacterial Proteins / chemistry*,  metabolism
Flavoproteins / chemistry*,  metabolism
Magnetic Resonance Spectroscopy
Models, Molecular
Protein Structure, Tertiary
Rhodobacter sphaeroides / metabolism*
Signal Transduction
Tryptophan / chemistry*
Grant Support
Reg. No./Substance:
0/AppA protein, Rhodobacter sphaeroides; 0/Bacterial Proteins; 0/Flavoproteins; 8DUH1N11BX/Tryptophan

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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