The corrin moiety of coenzyme B12 is the determinant for switching the btuB riboswitch of E. coli.
Riboswitches are regulatory elements in the 5'-untranslated region (5'-UTR) of bacterial mRNAs that bind certain metabolites with high specificity and affinity. The 202 nucleotide (nt)-long btuB riboswitch RNA of E. coli interacts specifically with coenzyme B12 and its derivatives thereby leading to changes in the RNA structure and hence to an altered expression of the downstream btuB gene. We report the investigations of the rearrangement of the three-dimensional structure of the btuB riboswitch upon binding to four different B12 derivatives: coenzyme B12, vitamin B12, adenosyl factor A and adenosyl-cobinamide. In-line probing experiments have shown that the corrin ring plays the crucial role in switching the three-dimensional riboswitch structure. Instead, the apical ligands influence only the binding affinity of the B12 derivative to the btuB riboswitch.
Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
Sofia
S
Gallo
Michael
M
Oberhuber
Roland K O
RK
Sigel
Bernhard
B
Kräutler
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D003035:Cobalt / Q000378:metabolism; D003067:Coenzymes / Q000737:chemistry* / Q000378:metabolism*; D045728:Corrinoids / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D008024:Ligands; D026901:Membrane Transport Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D012329:RNA, Bacterial / Q000235:genetics* / Q000378:metabolism; D038621:Regulatory Sequences, Ribonucleic Acid / Q000235:genetics*
D001425:Bacterial Outer Membrane Proteins; C044592:BtuB protein, E coli; D003067:Coenzymes; D045728:Corrinoids; D029968:Escherichia coli Proteins; D008024:Ligands; D026901:Membrane Transport Proteins; D012329:RNA, Bacterial; D038621:Regulatory Sequences, Ribonucleic Acid; C473700:corrin; D003035:Cobalt