|
MicL SRNA
MicL RNA (mRNA-interfering complementary RNA regulator of Lpp) is a sigma factor, σ E transcription factor-dependent small non-coding RNA. It was discovered in ''E. coli.'' Together with MicA RNA, MicA and RybB RNA, RybB sRNAs, MicL sRNA down-regulates the synthesis of abundant outer membrane proteins in response to stress. MicL specifically targets mRNA of lipoprotein Lpp, preventing its translation. References Non-coding RNA RNA RNA-binding proteins {{genetics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Structure
Protein secondary structure is the three dimensional form of ''local segments'' of proteins. The two most common secondary structural elements are 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 folds into its three dimensional tertiary structure. Secondary structure is formally defined by the pattern of hydrogen bonds between the amino hydrogen and carboxyl oxygen atoms in the peptide backbone. Secondary structure may alternatively be defined based on the regular pattern of backbone 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 Linderstrøm-Lang at Stanford in 1952. Other types of biopolymers such as nucleic acids also possess characteristic secondary structures. Types The most common secondary st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Conservation
In evolutionary biology, conserved sequences are identical or similar Sequence (biology), sequences in nucleic acids (DNA sequence, DNA and RNA) or peptide sequence, proteins across species (homology (biology)#Orthology, orthologous sequences), or within a genome (homology (biology)#Paralogy, paralogous sequences), or between donor and receptor taxa (Sequence homology#Xenology, xenologous sequences). Conservation indicates that a sequence has been maintained by natural selection. A highly conserved sequence is one that has remained relatively unchanged far back up the phylogenetic tree, and hence far back in geological time. Examples of highly conserved sequences include the Ribosomal RNA, RNA components of ribosomes present in all domain (biology), domains of life, the homeobox sequences widespread amongst Eukaryotes, and the tmRNA in Bacteria. The study of sequence conservation overlaps with the fields of genomics, proteomics, evolutionary biology, phylogenetics, bioinformatics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigma Factor
A sigma factor (σ factor or specificity factor) is a protein needed for initiation of transcription in bacteria. It is a bacterial transcription initiation factor that enables specific binding of RNA polymerase (RNAP) to gene promoters. It is homologous to archaeal transcription factor B and to eukaryotic factor TFIIB. The specific sigma factor used to initiate transcription of a given gene will vary, depending on the gene and on the environmental signals needed to initiate transcription of that gene. Selection of promoters by RNA polymerase is dependent on the sigma factor that associates with it. They are also found in plant chloroplasts as a part of the bacteria-like plastid-encoded polymerase (PEP). The sigma factor, together with RNA polymerase, is known as the RNA polymerase holoenzyme. Every molecule of RNA polymerase holoenzyme contains exactly one sigma factor subunit, which in the model bacterium ''Escherichia coli'' is one of those listed below. The number of sigma f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-coding RNA
A non-coding RNA (ncRNA) is a functional RNA molecule that is not translated into a protein. The DNA sequence from which a functional non-coding RNA is transcribed is often called an RNA gene. Abundant and functionally important types of non-coding RNAs include transfer RNAs (tRNAs) and ribosomal RNAs (rRNAs), as well as small RNAs such as microRNAs, siRNAs, piRNAs, snoRNAs, snRNAs, exRNAs, scaRNAs and the long ncRNAs such as Xist and HOTAIR. The number of non-coding RNAs within the human genome is unknown; however, recent transcriptomic and bioinformatic studies suggest that there are thousands of non-coding transcripts. Many of the newly identified ncRNAs have not been validated for their function. There is no consensus in the literature on how much of non-coding transcription is functional. Some researchers have argued that many ncRNAs are non-functional (sometimes referred to as "junk RNA"), spurious transcriptions. Others, however, disagree, arguing instead ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MicA RNA
The MicA RNA (also known as SraD) is a small non-coding RNA that was discovered in ''E. coli'' during a large scale screen. Expression of SraD is highly abundant in Stationary phase (biology), stationary phase, but low levels could be detected in bacterial growth, exponentially growing cells as well. Function This RNA binds the Hfq protein and regulates levels of gene expression by an antisense RNA, antisense mechanism. It is known to target the OmpA gene in ''E. coli'' and occludes the ribosome binding site. Under conditions of envelope stress, micA transcription is induced. MicA, RybB RNA and MicL sRNA, MicL RNA transcription is under the control of the sigma factor sigma(E). In ''E.coli'', SraD also interacts in ''cis'' and ''trans'' with the mRNA species, ''luxS'', ''ompA a''nd ''phoP'', respectively. This observation describes MicA to be the first known sRNA to carry out antisense regulation in both structural configurations. MicA is known to interact with the mRNA encoding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RybB RNA
RybB is a small non-coding RNA was identified in a large scale screen of ''Escherichia coli''. The function of this short RNA has been studied using a transcriptomic approach and kinetic analyses of target mRNA decay ''in vivo''. RybB was identified as a factor that selectively accelerates the decay of multiple major omp mRNAs upon induction of the envelope stress response. This RNA has been shown to bind to the Hfq protein. In ''Salmonella'', direct interactions for RybB with the following targets have been verified experimentally: STM2391 (''fadL''), STM1070 (''ompA''), STM2267 (''ompC''), STM1572 (''ompD''), STM0999 (''ompF''), STM1473 (''ompN''), STM1995 (''ompS''), STM1732 (''ompW''), STM0413 (''tsx''), STM0687 (''ybfM'', ''chiP'') and STM1530. In ''Escherichia coli'', direct interactions for RybB with the following targets have been verified experimentally: b0805 (''fiu''), b0721 (''sdhC''), b2215 (''ompC''), b1256 (''ompW''), b2594 (''rluD'') and b0081 (''mraZ''). See also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-coding RNA
A non-coding RNA (ncRNA) is a functional RNA molecule that is not translated into a protein. The DNA sequence from which a functional non-coding RNA is transcribed is often called an RNA gene. Abundant and functionally important types of non-coding RNAs include transfer RNAs (tRNAs) and ribosomal RNAs (rRNAs), as well as small RNAs such as microRNAs, siRNAs, piRNAs, snoRNAs, snRNAs, exRNAs, scaRNAs and the long ncRNAs such as Xist and HOTAIR. The number of non-coding RNAs within the human genome is unknown; however, recent transcriptomic and bioinformatic studies suggest that there are thousands of non-coding transcripts. Many of the newly identified ncRNAs have not been validated for their function. There is no consensus in the literature on how much of non-coding transcription is functional. Some researchers have argued that many ncRNAs are non-functional (sometimes referred to as "junk RNA"), spurious transcriptions. Others, however, disagree, arguing instead ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
