PDBsum entry 5o2t

Signaling protein

PDB id: 5o2t

Contents

Protein chains

164 a.a.

142 a.a.

Ligands

GSP

SO4 ×2

Metals

_MG

Waters ×85

PDB id:

5o2t

Name:

Signaling protein

Title:

Human kras in complex with darpin k27

Structure:

Gtpase kras. Chain: a. Synonym: k-ras 2,ki-ras,c-k-ras,c-ki-ras. Engineered: yes. Darpin 55. Chain: b. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: kras, kras2, rask2. Expressed in: escherichia coli. Expression_system_taxid: 562. Expression_system_taxid: 562

Resolution:

2.19Å R-factor: 0.184 R-free: 0.229

Authors:

J.E.Debreczeni,S.Guillard,P.Kolasinska-Zwierz,J.Breed,J.Zhang,N.Bery, R.Marwood,J.Tart,P.Stocki,B.Mistry,C.Phillips,T.Rabbitts,R.Jackson, R.Minter

Key ref:

S.Guillard et al. (2017). Structural and functional characterization of a DARPin which inhibits Ras nucleotide exchange. Nat Commun, 8, 16111. PubMed id: 28706291

Date:

22-May-17 Release date: 26-Jul-17

Protein chain

P01116  (RASK_HUMAN) -  GTPase KRas from Homo sapiens

Seq: 189 a.a.

Struc: 164 a.a.*

Protein chain

No UniProt id for this chain

Struc: 142 a.a.

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

Enzyme reactions

• Enzyme class: Chain A: E.C.3.6.5.2 - small monomeric GTPase.
• Reaction: GTP + H2O = GDP + phosphate + H⁺

GTP (Bound ligand (Het Group name = GSP) matches with 93.94% similarity) + H2O = GDP + phosphate + H(+)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Nat Commun 8:16111 (2017)

PubMed id: 28706291

Structural and functional characterization of a DARPin which inhibits Ras nucleotide exchange.

S.Guillard, P.Kolasinska-Zwierz, J.Debreczeni, J.Breed, J.Zhang, N.Bery, R.Marwood, J.Tart, R.Overman, P.Stocki, B.Mistry, C.Phillips, T.Rabbitts, R.Jackson, R.Minter.

ABSTRACT

Ras mutations are the oncogenic drivers of many human cancers and yet there are still no approved Ras-targeted cancer therapies. Inhibition of Ras nucleotide exchange is a promising new approach but better understanding of this mechanism of action is needed. Here we describe an antibody mimetic, DARPin K27, which inhibits nucleotide exchange of Ras. K27 binds preferentially to the inactive Ras GDP form with a K_dof 4 nM and structural studies support its selectivity for inactive Ras. Intracellular expression of K27 significantly reduces the amount of active Ras, inhibits downstream signalling, in particular the levels of phosphorylated ERK, and slows the growth in soft agar of HCT116 cells. K27 is a potent, non-covalent inhibitor of nucleotide exchange, showing consistent effects across different isoforms of Ras, including wild-type and oncogenic mutant forms.