Publication Date:
2015-09-30
Description:
Photoreceptor proteins enable organisms to sense and respond to light. The newly discovered CarH-type photoreceptors use a vitamin B12 derivative, adenosylcobalamin, as the light-sensing chromophore to mediate light-dependent gene regulation. Here we present crystal structures of Thermus thermophilus CarH in all three relevant states: in the dark, both free and bound to operator DNA, and after light exposure. These structures provide visualizations of how adenosylcobalamin mediates CarH tetramer formation in the dark, how this tetramer binds to the promoter -35 element to repress transcription, and how light exposure leads to a large-scale conformational change that activates transcription. In addition to the remarkable functional repurposing of adenosylcobalamin from an enzyme cofactor to a light sensor, we find that nature also repurposed two independent protein modules in assembling CarH. These results expand the biological role of vitamin B12 and provide fundamental insight into a new mode of light-dependent gene regulation.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4634937/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4634937/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jost, Marco -- Fernandez-Zapata, Jesus -- Polanco, Maria Carmen -- Ortiz-Guerrero, Juan Manuel -- Chen, Percival Yang-Ting -- Kang, Gyunghoon -- Padmanabhan, S -- Elias-Arnanz, Montserrat -- Drennan, Catherine L -- GM069857/GM/NIGMS NIH HHS/ -- P41 GM103393/GM/NIGMS NIH HHS/ -- P41 GM103403/GM/NIGMS NIH HHS/ -- P41GM103393/GM/NIGMS NIH HHS/ -- P41GM103403/GM/NIGMS NIH HHS/ -- R01 GM069857/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2015 Oct 22;526(7574):536-41. doi: 10.1038/nature14950. Epub 2015 Sep 28.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA. ; Instituto de Quimica Fisica "Rocasolano", Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain. ; Department of Genetics and Microbiology, Area of Genetics (Unidad Asociada al Instituto de Quimica Fisica "Rocasolano", Consejo Superior de Investigaciones Cientificas), Faculty of Biology, Universidad de Murcia, Murcia 30100, Spain. ; Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA. ; Howard Hughes Medical Institute, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26416754" target="_blank"〉PubMed〈/a〉
Keywords:
Amino Acid Sequence
;
Bacterial Proteins/*chemistry/*genetics/metabolism
;
Base Sequence
;
Cobamides/*metabolism/radiation effects
;
Crystallography, X-Ray
;
DNA, Bacterial/genetics/metabolism
;
Darkness
;
Dimerization
;
*Gene Expression Regulation, Bacterial/radiation effects
;
Light
;
Models, Molecular
;
Molecular Sequence Data
;
Operator Regions, Genetic/genetics
;
Promoter Regions, Genetic/genetics
;
Protein Structure, Quaternary/radiation effects
;
*Thermus thermophilus/chemistry/genetics/radiation effects
;
Transcription, Genetic/genetics/radiation effects
;
Vitamin B 12/*metabolism/radiation effects
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
