The anti-hemB RNA motif is a conserved

RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...

structure that was found in all known

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 ...

in the genus ''

Burkholderia ''Burkholderia'' is a genus of Pseudomonadota whose pathogenic members include the ''Burkholderia cepacia'' complex, which attacks humans and ''Burkholderia mallei'', responsible for glanders, a disease that occurs mostly in horses and related a ...

'', and in a variety of other

betaproteobacteria Betaproteobacteria are a class of Gram-negative bacteria, and one of the eight classes of the phylum Pseudomonadota (synonym Proteobacteria). The ''Betaproteobacteria'' are a class comprising over 75 genera and 400 species of bacteria. Togeth ...

. The anti-hemB RNA motif consists primarily of two

stem-loop Stem-loop intramolecular base pairing is a pattern that can occur in single-stranded RNA. The structure is also known as a hairpin or hairpin loop. It occurs when two regions of the same strand, usually complementary in nucleotide sequence when ...

s, followed by a predicted

rho-independent transcription termination Intrinsic, or rho-independent termination, is a process in prokaryotes to signal the end of transcription and release the newly constructed RNA molecule. In prokaryotes such as E. coli, transcription is terminated either by a rho-dependent process ...

stem-loop. As anti-hemB RNAs are generally not located in a

5' UTR The 5′ untranslated region (also known as 5′ UTR, leader sequence, transcript leader, or leader RNA) is the region of a messenger RNA (mRNA) that is directly upstream from the initiation codon. This region is important for the regulation of ...

, the RNAs are presumed to be

non-coding RNAs 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-c ...

. The terminator stem-loop implies that anti-hemB RNAs are transcribed as independent molecules. The name "anti-hemB" is to distinguish the motif from its reverse complement, which was called the "hemB" motif, a motif that is often in the apparent 5' UTRs of ''hemB'' genes. It was considered ambiguous as to which of these orientations is correct, as both directions exhibit covariation (see secondary structure prediction), and both fold into plausible RNA structures. However, the anti-hemB was judged the more likely orientation, because it had fewer A-C

base pair A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...

s, which do not contribute to RNA stability. In reverse complement, an A-C pair becomes the stable G-U wobble pair.

References

Non-coding RNA {{molecular-cell-biology-stub