PDBsum entry 6fyh

Ligase

PDB id: 6fyh

Contents

Protein chains

115 a.a.

76 a.a.

Ligands

SO4 ×2

Metals

_ZN ×6

Waters ×5

PDB id:

6fyh

Name:

Ligase

Title:

Disulfide between ubiquitin g76c and the e3 hect ligase huwe1

Structure:

E3 ubiquitin-protein ligase huwe1. Chain: a. Synonym: arf-binding protein 1,arf-bp1,hect,uba and wwe domain- containing protein 1,hect-type e3 ubiquitin transferase huwe1, homologous to e6ap carboxyl terminus homologous protein 9,hecth9, large structure of ureb1,lasu1,mcl-1 ubiquitin ligase e3,mule, upstream regulatory element-binding protein 1,ure-binding protein 1. Engineered: yes. Mutation: yes.

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: huwe1, kiaa0312, kiaa1578, ureb1, hspc272. Expressed in: escherichia coli. Expression_system_taxid: 562. Gene: ubb. Expression_system_taxid: 562

Resolution:

2.91Å R-factor: 0.232 R-free: 0.266

Authors:

M.Jaeckl,M.D.Hartmann,S.Wiesner

Key ref:

M.Jäckl et al. (2018). β-Sheet Augmentation Is a Conserved Mechanism of Priming HECT E3 Ligases for Ubiquitin Ligation. J Mol Biol, 430, 3218-3233. PubMed id: 29964046 DOI: 10.1016/j.jmb.2018.06.044

Date:

12-Mar-18 Release date: 11-Jul-18

Protein chain

Q7Z6Z7  (HUWE1_HUMAN) -  E3 ubiquitin-protein ligase HUWE1 from Homo sapiens

Seq: 4374 a.a.

Struc: 115 a.a.*

Protein chain

P0CG47  (UBB_HUMAN) -  Polyubiquitin-B from Homo sapiens

Seq: 229 a.a.

Struc: 76 a.a.

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: Chain A: E.C.2.3.2.26 - HECT-type E3 ubiquitin transferase.
• Reaction: S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N₆- ubiquitinyl-[acceptor protein]-L-lysine

DOI no: 10.1016/j.jmb.2018.06.044

J Mol Biol 430:3218-3233 (2018)

PubMed id: 29964046

β-Sheet Augmentation Is a Conserved Mechanism of Priming HECT E3 Ligases for Ubiquitin Ligation.

M.Jäckl, C.Stollmaier, T.Strohäker, K.Hyz, E.Maspero, S.Polo, S.Wiesner.

ABSTRACT

Ubiquitin (Ub) ligases (E3s) catalyze the attachment of Ub chains to target proteins and thereby regulate a wide array of signal transduction pathways in eukaryotes. In HECT-type E3s, Ub first forms a thioester intermediate with a strictly conserved Cys in the C-lobe of the HECT domain and is then ligated via an isopeptide bond to a Lys residue in the substrate or a preceding Ub in a poly-Ub chain. To date, many key aspects of HECT-mediated Ub transfer have remained elusive. Here, we provide structural and functional insights into the catalytic mechanism of the HECT-type ligase Huwe1 and compare it to the unrelated, K63-specific Smurf2 E3, a member of the Nedd4 family. We found that the Huwe1 HECT domain, in contrast to Nedd4-family E3s, prioritizes K6- and K48-poly-Ub chains and does not interact with Ub in a non-covalent manner. Despite these mechanistic differences, we demonstrate that the architecture of the C-lobe~Ub intermediate is conserved between Huwe1 and Smurf2 and involves a reorientation of the very C-terminal residues. Moreover, in Nedd4 E3s and Huwe1, the individual sequence composition of the Huwe1 C-terminal tail modulates ubiquitination activity, without affecting thioester formation. In sum, our data suggest that catalysis of HECT ligases hold common features, such as the β-sheet augmentation that primes the enzymes for ligation, and variable elements, such as the sequence of the HECT C-terminal tail, that fine-tune ubiquitination activity and may aid in determining Ub chain specificity by positioning the substrate or acceptor Ub.