Identification of a substrate recognition site on Ubc9.

D Lin, HM Tatham, B Yu, S Kim, Ronald Thomas Hay, Y Chen

Research output: Contribution to journalArticlepeer-review

105 Citations (Scopus)

Abstract

Human Ubc9 is homologous to ubiquitin-conjugating enzymes. However, instead of conjugating ubiquitin, it conjugates a ubiquitin homologue, small ubiquitin-like modifier 1 (SUMO-1), also known as UBL1, GMP1, SMTP3, PIC1, and sentrin. The SUMO-1 conjugation pathway is very similar to that of ubiquitin with regard to the primary sequences of the ubiquitin-activating enzymes (El), the three-dimensional structures of the ubiquitin-conjugating enzymes (E2), and the chemistry of the overall conjugation pathway. The interaction of substrates with Ubc9 has been studied using NMR spectroscopy. Peptides with sequences that correspond to those of the SUMO-1 conjugation sites from p53 and c-Jun both bind to a surface adjacent to the active site Cys(93) of human Ubc9, which has been previously shown to include residues that demonstrate the most significant dynamics on the microsecond to millisecond time scale. Mutations in this region, Q126A, Q130A, A131D, E132A, Y134A, and T135A, were constructed to evaluate the role of these residues in SUMO-1 conjugation. These alterations have significant effects on the conjugation of SUMO-1 with the target proteins p53, E1B, and promyelocytic leukemia protein and define a substrate binding site on Ubc9. Furthermore, the SUMO-1 conjugation site of p53 does not form any defined secondary structure when either free or bound to Ubc9. This suggests that a defined secondary structure at SUMO-1 conjugation sites in target proteins is not necessary for recognition and conjugation by the SUMO-1 pathway.

Original languageEnglish
Pages (from-to)21740-21748
Number of pages9
JournalJournal of Biological Chemistry
Volume277
DOIs
Publication statusPublished - 14 Jun 2002

Keywords

  • UBIQUITIN-CONJUGATING ENZYMES
  • SUMO-1 MODIFICATION
  • CRYSTAL-STRUCTURE
  • SACCHAROMYCES-CEREVISIAE
  • ANGSTROM RESOLUTION
  • ACTIVATING ENZYME
  • BINDING INTERFACE
  • PROTEIN SUMO-1
  • NUCLEAR-BODIES
  • YEAST SEPTINS

Fingerprint

Dive into the research topics of 'Identification of a substrate recognition site on Ubc9.'. Together they form a unique fingerprint.

Cite this