A novel ubiquitin binding mode in the S. cerevisiae translesion synthesis DNA polymerase η

Yongxing Ai, Jialiang Wang, Robert E. Johnson, Lajos Haracska, Louise Prakash, Zhihao Zhuang

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The ubiquitin binding zinc finger (UBZ) domain in the C-terminal portion of Polη has been found to interact with ubiquitin. However, the affinity between the Polη UBZ and ubiquitin was shown to be low with a previously reported K d of 73-81 μM. This low-affinity binding between Polη UBZ and ubiquitin has been difficult to reconcile with its presumed role in translesion synthesis as suggested by genetic and cell biology studies. In this work, we constructed a minimal S. cerevisiae Polη UBZ domain and probed the Polη UBZ-ubiquitin interaction using a surface plasmon resonance (SPR) technique. Our quantitative binding data between the wild-type or mutant Polη UBZ and ubiquitin revealed an interesting divergence between the Polη UBZ from S. cerevisiae and humans. Moreover, we found that the C-terminal portion of yeast Polη (amino acid 515-632) binds ubiquitin with a much higher affinity than the minimal UBZ domain. Further, distinct ubiquitin-binding kinetics were observed for the C-terminal portion of Polη and the isolated UBZ domain. This observation raised the interesting possibility that the Polη C-terminal portion binds ubiquitin in a novel mode that affords higher affinity. Our findings have broader implication in understanding the generally weak interaction between the known ubiquitin-binding domains and ubiquitin.

Original languageEnglish (US)
Pages (from-to)1874-1882
Number of pages9
JournalMolecular BioSystems
Volume7
Issue number6
DOIs
StatePublished - Jun 1 2011

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Biology

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