7OPR

Rab27a fusion with Slp2a-RBDa1 effector covalent adduct with CB1 in C123

Summary for 7OPR

• Entry DOI: 10.2210/pdb7opr/pdb
• Descriptor: Synaptotagmin-like protein 2,Ras-related protein Rab-27A, PHOSPHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER, MAGNESIUM ION, ... (6 entities in total)
• Functional Keywords: gtpase, exosome, acrylamide, cysteine-reactive, exocytosis
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 2
• Total formula weight: 54224.87

Authors

Jamshidiha, M.,Tersa, M.,Lanyon-Hogg, T.,Perez-Dorado, I.,Sutherell, C.L.,De Vita, E.,Morgan, R.M.L.,Tate, E.W.,Cota, E. (deposition date: 2021-06-01, release date: 2022-04-06, Last modification date: 2024-10-23)

Primary citation

Jamshidiha, M.,Lanyon-Hogg, T.,Sutherell, C.L.,Craven, G.B.,Tersa, M.,De Vita, E.,Brustur, D.,Perez-Dorado, I.,Hassan, S.,Petracca, R.,Morgan, R.M.,Sanz-Hernandez, M.,Norman, J.C.,Armstrong, A.,Mann, D.J.,Cota, E.,Tate, E.W.
Identification of the first structurally validated covalent ligands of the small GTPase RAB27A.
Rsc Med Chem, 13:150-155, 2022

PubMed Abstract: Rab27A is a small GTPase, which mediates transport and docking of secretory vesicles at the plasma membrane protein-protein interactions (PPIs) with effector proteins. Rab27A promotes the growth and invasion of multiple cancer types such as breast, lung and pancreatic, by enhancing secretion of chemokines, metalloproteases and exosomes. The significant role of Rab27A in multiple cancer types and the minor role in adults suggest that Rab27A may be a suitable target to disrupt cancer metastasis. Similar to many GTPases, the flat topology of the Rab27A-effector PPI interface and the high affinity for GTP make it a challenging target for inhibition by small molecules. Reported co-crystal structures show that several effectors of Rab27A interact with the Rab27A SF4 pocket ('WF-binding pocket') a conserved tryptophan-phenylalanine (WF) dipeptide motif. To obtain structural insight into the ligandability of this pocket, a novel construct was designed fusing Rab27A to part of an effector protein (fRab27A), allowing crystallisation of Rab27A in high throughput. The paradigm of KRas covalent inhibitor development highlights the challenge presented by GTPase proteins as targets. However, taking advantage of two cysteine residues, C123 and C188, that flank the WF pocket and are unique to Rab27A and Rab27B among the >60 Rab family proteins, we used the quantitative Irreversible Tethering (qIT) assay to identify the first covalent ligands for native Rab27A. The binding modes of two hits were elucidated by co-crystallisation with fRab27A, exemplifying a platform for identifying suitable lead fragments for future development of competitive inhibitors of the Rab27A-effector interaction interface, corroborating the use of covalent libraries to tackle challenging targets.

PubMed: 35308027
DOI: 10.1039/d1md00225b

Experimental method

X-RAY DIFFRACTION (2.32 Å)