HP Hairpin Reagent (7-deaza dATP, 1ml)

Enzovera HP Hairpin Reagent (EV-SGR-010) is a 7-deaza-2′-deoxyadenosine triphosphate (7-deaza dATP) sequencing additive for resolving difficult Sanger templates with strong secondary structures, GC-rich hairpins, and homopolymeric runs. The reagent substitutes for standard dATP in the cycle sequencing reaction to destabilize secondary structure in the newly synthesized strand, producing cleaner sequence reads through problematic regions that would otherwise cause compression artifacts, signal dropout, or premature termination.

Mechanism of structure resolution. 7-deaza dATP is a modified deoxyadenosine analog in which the N7 nitrogen of the purine ring is replaced with a carbon atom. This substitution preserves Watson-Crick base pairing with thymine — the modified nucleotide reads as adenosine during DNA synthesis — but eliminates the Hoogsteen face hydrogen bond donor/acceptor positions that normally stabilize G-quadruplexes, triple helices, and certain hairpin structures. When 7-deaza dATP is incorporated into the newly synthesized DNA strand in place of standard dATP, the resulting strand cannot form the stable secondary structures that cause CE compression artifacts, allowing the strand to migrate through the CE polymer matrix in a fully denatured state and yielding evenly spaced, accurately base-called peaks through previously unreadable regions.

When to use. Add HP Hairpin Reagent to the standard sequencing reaction when sequencing templates with one or more of the following characteristics: GC content above 65–70%, palindromic sequences with predicted hairpin Tm above 50°C, long G-rich tracts (potential G-quadruplex formation), AT-rich palindromes, or known historical sequencing difficulty on the template region. Typical addition is 0.5–2 μL per standard sequencing reaction, partially or fully substituting for the dATP in the reaction mix; the optimal substitution ratio is determined empirically per template.

Compatibility. HP Hairpin Reagent is compatible with VeraDye™ Terminator v3.1 Cycle Sequencing Kit (EV-SGR-002) and with standard BigDye-format cycle sequencing chemistries. The reagent does not change CE run modules, mobility files, or instrument calibration — only the template-resolution chemistry in the reaction tube is modified.

Recommended applications:

• Sequencing of GC-rich genomic regions (CpG islands, promoter regions, GC-rich exons)
• Sequencing through long homopolymer runs (poly-A, poly-T, poly-G, poly-C tracts)
• Sequencing of palindromic regions and inverted repeats
• Sequencing of cloning vector junctions in difficult-to-read MCS regions
• Re-sequencing of regions that gave compressed or unreadable peaks on standard chemistry
• Sequencing of templates with predicted G-quadruplex or triplex-forming potential

Pack size: 1 mL per tube. Store at −20°C. Stable for 24 months in single-use aliquots. Avoid repeated freeze-thaw.