Citrulline aptamer
Timeline
The first in vitro screening of L-citrulline RNA aptamers and their evolution into an L-arginine binder[1]
Structural probing and damage selection of citrulline- and arginine-specific RNA aptamers identify base positions required for binding[2]
Another RNA aptamers that bind L-arginine with sub-micromolar dissociation constants and high enantioselectivity[3]
A stable 38-mer L-oligonucleotide ligand that binds L-arginine and a short peptide containing the basic region of the HIV-1 Tat protein[5]
Description
In 1994, Michael Famulok employed in vitro selection techniques to isolate aptamers with high-affinity binding sites for L-Citrulline. Subsequently, following the selection for L-citrulline, one of the citrulline-binding sequences (Clone 16) was used to generate a mutated pool for further selection. The capability to shift binding specificity from L-citrulline to L-arginine was demonstrated. In 1996, Michael Famulok et al. elucidated the structure of the aptamer complexed with L-Citrulline and L-arginine using multidimensional nuclear magnetic resonance spectroscopy and molecular dynamics calculations[1].SELEX
The SELEX began with an initial RNA pool consisting of approximately 10^15different RNA molecules.This pool was subjected to in vitro selection targeting specific binding to L-citrulline.RNA molecules that demonstrated affinity for L-citrulline were isolated using an epoxy-activated Sepharose 6B agarose column, to which L-citrulline was coupled. After seven cycles, the selected RNA pool was cloned and sequenced. Sequencing of 21 aptamers from this pool revealed 19 different sequences, with two sequences appearing twice, indicating a convergence towards certain sequence motifs that have higher affinity for L-citrulline. Following the selection for L-citrulline, one of the citrulline-binding sequences (Clone 16) was used to generate a mutated pool for further selection.The pool was mutated at a rate of 30% per base position to introduce diversity and potential for adaptation to new targets.This mutated pool was then used in subsequent selection cycles aimed at isolating RNA aptamers with binding specificity for L-arginine. After four cycles, 22 sequences derived from the L-arginine pool were analyzed.Of these, 11 sequences were found to potentially fold into a motif slightly different from the L-citrulline-binding motif but were highly specific to L-arginine[1].
Detailed information are accessible on SELEX page.
Structure
2D representation
Here we used ribodraw to complete the figure, through the 3D structure information[1].
A:5'-AGAAGGAGUGU-3'
B:5'-ACGGUUAGGUCGCU-3'
|
Binding pocket
Left: Surface representation of the binding pocket of the aptamer generated from PDB ID: 1KOD by NMR. Citrulline (shown in sticks) is labeled in yellow. Right: The hydrogen bonds of binding sites of the aptamer bound with Citrulline[4].Ligand information
SELEX ligand
The determination of the dissociation constants Kd for L-citrulline RNA aptamers in solution was performed by Michael Famulok. The methods employed for this purpose were isocratic elution chromatography and equilibrium gel filtration, which allowed for a comprehensive assessment of the interaction stability and affinity under various experimental conditions. These methods enabled a robust evaluation of the binding affinity dynamics of RNA with L-citrulline across different environments[1].Structure ligand
L-citrulline is the L-enantiomer of citrulline. It has a role as an EC 1.14.13.39 (nitric oxide synthase) inhibitor, a protective agent, a nutraceutical, a micronutrient, a human metabolite, an Escherichia coli metabolite, a Saccharomyces cerevisiae metabolite and a mouse metabolite. It is an enantiomer of a D-citrulline. It is a tautomer of a L-citrulline zwitterion.-----from ChEBI
PubChem CID | Molecular Formula | MW | CAS | Solubility | Drugbank ID |
---|---|---|---|---|---|
9750 | C6H13N3O3 | 175.19 g/mol | 372-75-8 | ≥ 50 mg/mL | DB00155 |
Similar compound
We screened the compounds with great similarity to Citrulline and Arginine by using the ZINC database and showed some of the compounds' structure diagrams. For some CAS numbers not available, we will supplement them with Pubchem CID.
Zinc_id | Named | CAS | Pubchem CID | Structure |
---|---|---|---|---|
ZINC000001532749 | D-Arginine | 157-06-2 | 71070 | |
ZINC000004556609 | N5-Iminoethyl-L-Ornithine | NA | 40489058 | |
ZINC000001532525 | Arginine | 74-79-3 | 6322 | |
ZINC000002166829 | D-Citrulline | 13594-51-9 | 637599 |
References
[1] Molecular Recognition of Amino Acids by RNA-Aptamers: An L-Citrulline Binding RNA Motif and Its Evolution into an L-Arginine Binder.Michael Famulok
Journal of the American Chemical Society 1994 116 (5), 1698-1706 (1994)
[2] Structural probing and damage selection of citrulline- and arginine-specific RNA aptamers identify base positions required for binding.
P Burgstaller, M Kochoyan, M Famulok
Nucleic acids research. 1995 Dec 11;23(23):4769-76. (1995)
[3] RNA aptamers that bind L-arginine with sub-micromolar dissociation constants and high enantioselectivity.
A Geiger, P Burgstaller, H von der Eltz, A Roeder, M Famulok
Nucleic acids research. 1996 Mar 15;24(6):1029-36. (1996)
[4] Structural basis of ligand discrimination by two related RNA aptamers resolved by NMR spectroscopy.
Y Yang, M Kochoyan, P Burgstaller, E Westhof, M Famulok
Science. 1996 May 31;272(5266):1343-7. (1996)
[5] Mirror-design of L-oligonucleotide ligands binding to L-arginine.
A Nolte, S Klussmann, R Bald, V A Erdmann, J P Fürste
Nature biotechnology. 1996 Sep;14(9):1116-9. (1996)
[6] Chiral stationary phase based on a biostable L-RNA aptamer.
Agnès Brumbt, Corinne Ravelet, Catherine Grosset, Anne Ravel, Annick Villet, Eric Peyrin
Analytical chemistry. 2005 Apr 1;77(7):1993-8. (2005)