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Spot 42 RNA
Spot 42 (''spf'') RNA is a regulatory non-coding bacterial small RNA encoded by the spf (spot forty-two) gene. ''Spf'' is found in gammaproteobacteria and the majority of experimental work on Spot42 has been performed in ''Escherichia coli'' and recently in ''Aliivibrio salmonicida''. In the cell Spot42 plays essential roles as a regulator in carbohydrate metabolism and uptake, and its expression is activated by glucose, and inhibited by the cAMP- CRP complex. The sRNA is transcribed from a separate promoter and binds to messenger RNA targets through imperfect base pairing. The half-life of Spot42 ''in vivo'' is 12 to 13 minutes at 37 °C. When grown in media supplemented with glucose, each cell contains 100–200 Spot42 copies. The corresponding level is however reduced 3–4-fold when cells are grown in succinate or when cAMP is added to cells grown in glucose. Discovery Spot42 was first described in 1973 as an unstable RNA species of 109 nucleotides in ''Escherichia coli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Structure
Protein secondary structure is the three dimensional conformational isomerism, form of ''local segments'' of proteins. The two most common Protein structure#Secondary structure, secondary structural elements are alpha helix, alpha helices and beta sheets, though beta turns and omega loops occur as well. Secondary structure elements typically spontaneously form as an intermediate before the protein protein folding, folds into its three dimensional protein tertiary structure, tertiary structure. Secondary structure is formally defined by the pattern of hydrogen bonds between the Amine, amino hydrogen and carboxyl oxygen atoms in the peptide backbone chain, backbone. Secondary structure may alternatively be defined based on the regular pattern of backbone Dihedral angle#Dihedral angles of proteins, dihedral angles in a particular region of the Ramachandran plot regardless of whether it has the correct hydrogen bonds. The concept of secondary structure was first introduced by Kaj Ulrik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |