| ykoK leader | |
|---|---|
 Predicted secondary structure and sequence conservation of ykoK | |
| Identifiers | |
| Symbol | ykoK |
| Rfam | RF00380 |
| Other data | |
| RNA type | Cis-reg; riboswitch |
| Domain(s) | Bacteria |
| SO | SO:0000233 |
| PDB structures | PDBe |
The Ykok leader or M-box is a Mg-sensing RNA structure that controls the expression of Magnesium ion transport proteins in bacteria. It is a distinct structure to the Magnesium responsive RNA element.
The Ykok leader was originally described as a conserved sequence with potential riboswitch function found upstream of the B. subtilis ykoK gene and genes with related functions in other bacteria. Examples of the conserved M-box RNA structure occur upstream of each of the three major families of Mg transporters (CorA, MgtE and MgtA/MgtB) in various bacterial species.
The molecular structure of the M-box example upstream of the B. subtilis ykoK gene includes six bound Mg ions. Biochemical studies indicate that this M-Box RNA compacts in the presence of Mg and other divalent ions. This folding process appears to disrupt an antiterminator structure, and thereby allow a transcription terminator structure to form. As expected from this model, B. subtilis cells repress expression of a downstream reporter gene when grown in the presence of Mg. Therefore, the M-box appears to function as a genetic "off" switch that is important for maintaining Mg homeostasis in bacteria.
-
A 3D representation of the Ykok leader. Structure of the M-box riboswitch aptamer domain from Bacillus subtilis.
References
- Barrick, JE; Corbino KA; Winkler WC; Nahvi A; Mandal M; Collins J; Lee M; Roth A; Sudarsan N; Jona I; Wickiser JK; Breaker RR (2004). "New RNA motifs suggest an expanded scope for riboswitches in bacterial genetic control". Proc Natl Acad Sci USA. 101 (17): 6421–6426. Bibcode:2004PNAS..101.6421B. doi:10.1073/pnas.0308014101. PMC 404060. PMID 15096624.
- ^ Dann CE, Wakeman CA, Sieling CL, Baker SC, Irnov I, Winkler WC (2007). "Structure and mechanism of a metal-sensing regulatory RNA". Cell. 130 (5): 878–892. doi:10.1016/j.cell.2007.06.051. PMID 17803910. S2CID 13193104.
External links
 | This molecular or cell biology article is a stub. You can help Misplaced Pages by expanding it. |