5jne
From Proteopedia
E2-SUMO-Siz1 E3-SUMO-PCNA complex
Structural highlights
Function[PCNA_YEAST] This protein is an auxiliary protein of DNA polymerase delta and is involved in the control of eukaryotic DNA replication by increasing the polymerase's processibility during elongation of the leading strand. Involved in DNA repair.[1] [2] [SIZ1_YEAST] Acts as an E3 ligase mediating SUMO/Smt3 attachment to septins and PCNA. May be involved in chromosome maintenance.[3] [4] [5] [6] [7] [SMT3_YEAST] Not known; suppressor of MIF2 mutations. [UBC9_YEAST] E2 ubiquitin-like--protein ligase mediating SUMO/Smt3 attachment to septins and PCNA. Seems to be involved in degradation of S- (CLB5) and M-phase cyclins (CLB2).[8] [9] Publication Abstract from PubMedPost-translational protein modification by ubiquitin (Ub) and ubiquitin-like (Ubl) proteins such as small ubiquitin-like modifier (SUMO) regulates processes including protein homeostasis, the DNA damage response, and the cell cycle. Proliferating cell nuclear antigen (PCNA) is modified by Ub or poly-Ub at lysine (Lys)164 after DNA damage to recruit repair factors. Yeast PCNA is modified by SUMO on Lys164 and Lys127 during S-phase to recruit the anti-recombinogenic helicase Srs2. Lys164 modification requires specialized E2/E3 enzyme pairs for SUMO or Ub conjugation. For SUMO, Lys164 modification is strictly dependent on the E3 ligase Siz1, suggesting the E3 alters E2 specificity to promote Lys164 modification. The structural basis for substrate interactions in activated E3/E2-Ub/Ubl complexes remains unclear. Here we report an engineered E2 protein and cross-linking strategies that trap an E3/E2-Ubl/substrate complex for structure determination, illustrating how an E3 can bypass E2 specificity to force-feed a substrate lysine into the E2 active site. Capturing a substrate in an activated RING E3/E2-SUMO complex.,Streich FC Jr, Lima CD Nature. 2016 Aug 18;536(7616):304-8. PMID:27509863[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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