PDBsum entry 4lsx

Steroid binding protein/protein binding

PDB id: 4lsx

Contents

Protein chains

740 a.a.

185 a.a.

Ligands

NAG-NAG-BMA-MAN ×3

NAG-NAG ×2

NAG-NAG-BMA-MAN-MAN

NAG-NAG-BMA

BLD ×2

NAG ×7

PDB id:

4lsx

Name:

Steroid binding protein/protein binding

Title:

Plant steroid receptor ectodomain bound to brassinolide and serk1 co- receptor ectodomain

Structure:

Protein brassinosteroid insensitive 1. Chain: a, b. Fragment: receptor ectodomain/lrr-domain (unp residues 29-788). Synonym: atbri1, brassinosteroid lrr receptor kinase. Engineered: yes. Mutation: yes. Somatic embryogenesis receptor kinase 1. Chain: c, d. Fragment: co-receptor kinase ectodomain/lrr-domain (unp residues 24-

Source:

Arabidopsis thaliana. Mouse-ear cress. Organism_taxid: 3702. Strain: col 0. Gene: at4g39400, bri1, f23k16.30. Expressed in: trichoplusia ni. Expression_system_taxid: 7111. Gene: at1g71830, f14o23.21, f14o23_24, serk1.

Resolution:

3.30Å R-factor: 0.248 R-free: 0.285

Authors:

J.Santiago,C.Henzler,M.Hothorn

Key ref:

J.Santiago et al. (2013). Molecular mechanism for plant steroid receptor activation by somatic embryogenesis co-receptor kinases. Science, 341, 889-892. PubMed id: 23929946 DOI: 10.1126/science.1242468

Date:

23-Jul-13 Release date: 04-Sep-13

Protein chains

O22476  (BRI1_ARATH) -  Protein BRASSINOSTEROID INSENSITIVE 1 from Arabidopsis thaliana

Seq: 1196 a.a.

Struc: 740 a.a.*

Protein chains

Q94AG2  (SERK1_ARATH) -  Somatic embryogenesis receptor kinase 1 from Arabidopsis thaliana

Seq: 625 a.a.

Struc: 185 a.a.

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

Enzyme reactions

• Enzyme class 2: Chains A, B, C, D: E.C.2.7.10.1 - receptor protein-tyrosine kinase.
• Reaction: L-tyrosyl-[protein] + ATP = O-phospho-L-tyrosyl-[protein] + ADP + H⁺

L-tyrosyl-[protein] + ATP = O-phospho-L-tyrosyl-[protein] (Bound ligand (Het Group name = NAG) matches with 41.38% similarity) + ADP + H(+)

• Enzyme class 3: Chains A, B, C, D: E.C.2.7.11.1 - non-specific serine/threonine protein kinase.
• Reaction:
  1. L-seryl-[protein] + ATP = O-phospho-L-seryl-[protein] + ADP + H⁺
  2. L-threonyl-[protein] + ATP = O-phospho-L-threonyl-[protein] + ADP + H⁺

L-seryl-[protein] + ATP = O-phospho-L-seryl-[protein] (Bound ligand (Het Group name = NAG) matches with 41.38% similarity) + ADP + H(+)

L-threonyl-[protein] + ATP = O-phospho-L-threonyl-[protein] (Bound ligand (Het Group name = NAG) matches with 41.38% similarity) + ADP + H(+)

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

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

reference

DOI no: 10.1126/science.1242468

Science 341:889-892 (2013)

PubMed id: 23929946

Molecular mechanism for plant steroid receptor activation by somatic embryogenesis co-receptor kinases.

J.Santiago, C.Henzler, M.Hothorn.

ABSTRACT

Brassinosteroids, which control plant growth and development, are sensed by the leucine-rich repeat (LRR) domain of the membrane receptor kinase BRASSINOSTEROID INSENSITIVE 1 (BRI1), but it is unknown how steroid binding at the cell surface activates the cytoplasmic kinase domain of the receptor. A family of somatic embryogenesis receptor kinases (SERKs) has been genetically implicated in mediating early brassinosteroid signaling events. We found a direct and steroid-dependent interaction between the BRI1 and SERK1 LRR domains by analysis of their complex crystal structure at 3.3 angstrom resolution. We show that the SERK1 LRR domain is involved in steroid sensing and, through receptor-co-receptor heteromerization, in the activation of the BRI1 signaling pathway. Our work reveals how known missense mutations in BRI1 and in SERKs modulate brassinosteroid signaling and the targeting mechanism of BRI1 receptor antagonists.