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Why your AP-site DNA templates slip when you least expect it

Machine-readable facts for this Lab article. The full page is https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect.

TL;DR

HMCES cross-links to AP sites in single-stranded DNA, and that cross-link drives the biology. Even trimmed by SPRTN to a five-amino-acid peptide, it still acts.

Facts Index

Fact IDCategoryEntityAttributeValueSource
why-ap-site-dna-templates-slip-when-least-expect:titleidentityWhy your AP-site DNA templates slip when you least expect ittitleWhy your AP-site DNA templates slip when you least expect itLab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:publishedidentityWhy your AP-site DNA templates slip when you least expect itpublished2026-08-17Lab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:authoridentityWhy your AP-site DNA templates slip when you least expect itauthorPreppinPeppers Editorial TeamLab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:topicsidentityWhy your AP-site DNA templates slip when you least expect ittopicspeptide research, Research, studyLab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:summarycontentWhy your AP-site DNA templates slip when you least expect itsummaryHMCES cross-links to AP sites in single-stranded DNA, and that cross-link drives the biology. Even trimmed by SPRTN to a five-amino-acid peptide, it still acts.Lab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:section-1contentWhy your AP-site DNA templates slip when you least expect itsectionWhat HMCES DoesLab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:section-2contentWhy your AP-site DNA templates slip when you least expect itsectionWhat HMCES actually does to an AP siteLab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:section-3contentWhy your AP-site DNA templates slip when you least expect itsectionThe surprising result: it's the cross-link, not the peptide lengthLab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:section-4contentWhy your AP-site DNA templates slip when you least expect itsectionWhy this matters at the benchLab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:section-5contentWhy your AP-site DNA templates slip when you least expect itsectionThe bigger pictureLab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:source-www-biorxiv-orgsourceWhy your AP-site DNA templates slip when you least expect itcitesthis coverage at bioRxiv → - www.biorxiv.orgLab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:source-pmc-ncbi-nlm-nih-govsourceWhy your AP-site DNA templates slip when you least expect itcitesYudkina et al., Int J Mol Sci 2023: Bypass of Abasic Site-Peptide Cross-Links by Human Repair and Translesion DNA Polymerases - pmc.ncbi.nlm.nih.govLab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:product-gansulin-metal-peptide-penproductsWhy your AP-site DNA templates slip when you least expect itreferences productGansulin Pen · Reusable Click-Dial, 3 ml (1-60 Units)Lab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)
why-ap-site-dna-templates-slip-when-least-expect:product-gansulin-3ml-cartridgeproductsWhy your AP-site DNA templates slip when you least expect itreferences productGansulin-Compatible 3 ml Glass Cartridge for Pens (10-Pack)Lab article (https://www.preppinpeppers.com/blogs/the-lab/why-ap-site-dna-templates-slip-when-least-expect) (evidence)

FAQ

Does trimming HMCES off the AP site make bypass cleaner?
No. In Xenopus egg extracts, mutagenicity of HMCES-DPC bypass is insensitive to how much SPRTN has proteolyzed the cross-link; only cross-link formation itself matters, because it locks the AP site in a dynamic ring-opened state.
Why does the base 5' of the AP site change the mutation spectrum?
The cross-link increases conformational flexibility of the template, allowing the 5' template nucleotide to slip into the polymerase active site and direct insertion opposite the adducted AP site, producing context-dependent mutations.
Should I worry about HMCES in my cell extract lesion-bypass assay?
Yes. Any extract or lysate containing HMCES will form thiazolidine cross-links to true abasic sites in ssDNA, altering polymerase readouts compared with a synthetic THF or dSpacer mimic that cannot be cross-linkable.