DNA polymerase Family X: Function, structure, and cellular roles

Jennifer Yamtich, Joann B. Sweasy

Research output: Contribution to journalReview articlepeer-review

112 Scopus citations


The X family of DNA polymerases in eukaryotic cells consists of terminal transferase and DNA polymerases β, λ, and μ. These enzymes have similar structural portraits, yet different biochemical properties, especially in their interactions with DNA. None of these enzymes possesses a proofreading subdomain, and their intrinsic fidelity of DNA synthesis is much lower than that of a polymerase that functions in cellular DNA replication. In this review, we discuss the similarities and differences of three members of Family X: polymerases β, λ, and μ. We focus on biochemical mechanisms, structural variation, fidelity and lesion bypass mechanisms, and cellular roles. Remarkably, although these enzymes have similar three-dimensional structures, their biochemical properties and cellular functions differ in important ways that impact cellular function.

Original languageEnglish (US)
Pages (from-to)1136-1150
Number of pages15
JournalBiochimica et Biophysica Acta - Proteins and Proteomics
Issue number5
StatePublished - May 2010
Externally publishedYes


  • DNA polymerase
  • DNA repair
  • Family X
  • Fidelity of DNA synthesis
  • Genomic stability
  • Mutagenesis

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biophysics
  • Biochemistry
  • Molecular Biology


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