Inosine

When using an inosine base within a hybridization probe, this residue can form base-pairs with deoxyadenosine (dA), deoxycytidine (dC), deoxyguanosine (dG), or deoxythymidine (dT) residues on the target strand. Inosine bases can be used instead of wobbles and have the advantage that the hybridization probe is not "diluted" by the non-pairing components of the wobbles. Creative Biolabs offers comprehensive oligo modification and labeling services to meet the research needs of customers all around the world.

Figure 1. Inosine structure.

Introduction

An inosine base can be used as a hybridization probe and form base-pairs with dA, dC, dG or dT residues on the target strand during the translation process. This amino modification is one kind of 5' amino modifier. Lots of experiments have shown that deoxyinosine might be an "inert" base. However, it doesn't disturb DNA duplex formation and destabilize the duplex while it presents in an oligonucleotide sequence. Independent of sequence effects, the order of stability of base-pairings is I-C >> I-A > I-T = I-G. Inosine bases can be at any position within an oligonucleotide, and can be employed multiple times within a sequence.

Figure 2. Deoxyinosine structure.

Deoxyinosine is found in DNA but inosine is found in RNA. Inosine is a nucleic acid crucial for RNA editing. Adenosine deaminase (ADA) catalyzes the conversion of adenosine and deoxyadenosine to inosine and deoxyinosine, respectively. ADA-deficient individuals suffer from severe combined immunodeficiency (SCID) and are unable to produce significant numbers of mature T or B lymphocytes. This occurs as a consequence of the accumulation of ADA substrates or their metabolites. In terms of inosine, it is also an intermediate in a chain of purine nucleotides reactions required for muscle movements. Furthermore, deoxyinosine is found to be associated with purine nucleoside phosphorylase (PNP) deficiency, which is an inborn error of metabolism.

Why Inosine?

We recommend customers to choose inosine as modifiers if their samples have single nucleotide polymorphisms (SNPs). At the same time, choosing inosine as oligonucleotides modifiers is suitable if clients want to detect multiple variants of the particular target, such as looking at several strains of a microbe. Under these conditions, we suggest customers could use inosine as their first choice to modify their oligonucleotides.

Types of Inosine

Creative Biolabs offers several types of inosine. You can choose to add a two-, three- or four-base wobble, depending on the variation of bases that appear at that location. However, if you are unsure which base occurs, or if all four occur, it may be preferable to generate one oligo species containing inosine, which binds to all four DNA bases, at that particular site.

• Inosine
  

  Inosine is the most commonly employed degenerated modified base which more or less is a universal base. It can be incorporated at 5', 3' end, and internal of the oligonucleotide.

• Deoxyinosine
  

  Creative Biolabs can synthesize oligonucleotides that contain 2'-deoxyinosine. Deoxyinosine is a universal base that occurs naturally. To include a deoxyinosine base(s) in your oligo, simply place an "I" directly in your sequence.

Creative Biolabs is committed to offering high-quality inosine modification service for the oligonucleotide. We can use inosine to be incorporated at 5', 3' end, and internal of the oligonucleotides. Moreover, we provide deoxyinosine for customers to add "I" in oligonucleotides sequence. We have been collaborating with customers at the forefront of scientific discovery to enable everything from exploration to commercialization. If you want to find more about the different modifications of oligonucleotides, keep an eye on Creative Biolabs. If you have any special requirements, please don't hesitate to contact us.