dc.contributor.author
Schreiner, Madeleine
dc.contributor.author
Schlesinger, Ramona
dc.contributor.author
Heberle, Joachim
dc.contributor.author
Niemann, H. H.
dc.date.accessioned
2018-06-08T10:19:38Z
dc.date.available
2017-02-24T10:37:13.938Z
dc.identifier.uri
https://refubium.fu-berlin.de/handle/fub188/20246
dc.identifier.uri
http://dx.doi.org/10.17169/refubium-23551
dc.description.abstract
The transmembrane pump halorhodopsin in halophilic archaea translocates
chloride ions from the extracellular to the cytoplasmic side upon
illumination. In the ground state a tightly bound chloride ion occupies the
primary chloride-binding site (CBS I) close to the protonated Schiff base that
links the retinal chromophore to the protein. The light-triggered trans-cis
isomerization of retinal causes structural changes in the protein associated
with movement of the chloride ion. In reverse, chemical depletion of CBS I in
Natronomonas pharaonis halorhodopsin (NpHR) through deprotonation of the
Schiff base results in conformational changes of the protein: a state thought
to mimic late stages of the photocycle. Here, crystals of Halobacterium
salinarum halorhodopsin (HsHR) were soaked at high pH to provoke
deprotonation of the Schiff base and loss of chloride. The crystals changed
colour from purple to yellow and the occupancy of CBS I was reduced from 1 to
about 0.5. In contrast to NpHR, this chloride depletion did not cause
substantial conformational changes in the protein. Nevertheless, two
observations indicate that chloride depletion could eventually result in
structural changes similar to those found in NpHR. Firstly, the partially
chloride-depleted form of HsHR has increased normalized B factors in the
region of helix C that is close to CBS I and changes its conformation in NpHR.
Secondly, prolonged soaking of HsHR crystals at high pH resulted in loss of
diffraction. In conclusion, the conformation of the chloride-free protein may
not be compatible with this crystal form of HsHR despite a packing arrangement
that hardly restrains helices E and F that presumably move during ion
transport.
en
dc.format.extent
8 Seiten
dc.rights.uri
http://journals.iucr.org/services/copyrightpolicy.html
dc.subject
Halobacterium salinarum
dc.subject
archaeal rhodopsin
dc.subject
retinal protein
dc.subject
light-driven ion pump
dc.subject
post-crystallization treatment
dc.subject
reaction intermediate
dc.subject.ddc
500 Naturwissenschaften und Mathematik::530 Physik
dc.title
Crystal structure of Halobacterium salinarum halorhodopsin with a partially
depopulated primary chloride-binding site
dc.type
Wissenschaftlicher Artikel
dcterms.bibliographicCitation
Acta Crystallographica Section F Structural Biology Communications. - 72
(2016), 9, S.S. 692-699 © International Union of Crystallography
dc.identifier.sepid
52982
dcterms.bibliographicCitation.doi
10.1107/S2053230X16012796
dcterms.bibliographicCitation.url
http://dx.doi.org/10.1107/S2053230X16012796
refubium.affiliation
Physik
de
refubium.affiliation.other
Institut für Experimentalphysik
refubium.mycore.fudocsId
FUDOCS_document_000000026434
refubium.resourceType.isindependentpub
no
refubium.mycore.derivateId
FUDOCS_derivate_000000007767
dcterms.accessRights.openaire
open access
dcterms.isPartOf.issn
2053-230X