PDBsum entry 4b1v

Structural protein

PDB id: 4b1v

Contents

Protein chains

352 a.a.

26 a.a.

Ligands

EDO ×4

ATP ×2

LAB ×2

GOL ×2

Metals

_MG ×2

Waters ×603

PDB id:

4b1v

Name:

Structural protein

Title:

Structure of the phactr1 rpel-n domain bound to g-actin

Structure:

Actin, alpha skeletal muscle. Chain: a, b. Fragment: residues 2-377. Synonym: alpha skeletal muscle actin, alpha-actin-1. Phosphatase and actin regulator 1. Chain: m, n. Fragment: residues 138-162. Synonym: phosphatase and actin regulator 1\, isoform cra_c. Engineered: yes

Source:

Oryctolagus cuniculus. Rabbit. Organism_taxid: 9986. Tissue: muscle. Synthetic: yes. Mus musculus. House mouse. Organism_taxid: 10090

Resolution:

1.75Å R-factor: 0.182 R-free: 0.221

Authors:

S.Mouilleron,M.Wiezlak,N.O'Reilly,R.Treisman,N.Q.Mcdonald

Key ref:

S.Mouilleron et al. (2012). Structures of the Phactr1 RPEL domain and RPEL motif complexes with G-actin reveal the molecular basis for actin binding cooperativity. Structure, 20, 1960-1970. PubMed id: 23041370

Date:

12-Jul-12 Release date: 07-Nov-12

Protein chains

P68135  (ACTS_RABIT) -  Actin, alpha skeletal muscle from Oryctolagus cuniculus

Seq: 377 a.a.

Struc: 352 a.a.

Protein chains

Q2M3X8  (PHAR1_MOUSE) -  Phosphatase and actin regulator 1 from Mus musculus

Seq: 580 a.a.

Struc: 26 a.a.

Enzyme reactions

• Enzyme class 2: Chains A, B: E.C.3.6.4.- - ?????
• Enzyme class 3: Chains M, N: E.C.?

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.

Structure 20:1960-1970 (2012)

PubMed id: 23041370

Structures of the Phactr1 RPEL domain and RPEL motif complexes with G-actin reveal the molecular basis for actin binding cooperativity.

S.Mouilleron, M.Wiezlak, N.O'Reilly, R.Treisman, N.Q.McDonald.

ABSTRACT

The Phactr family of PP1-binding proteins and the myocardin-related transcription factor family of transcriptional coactivators contain regulatory domains comprising three copies of the RPEL motif, a G-actin binding element. We report the structure of a Phactr1 G-actin⋅RPEL domain complex. Three G-actins surround the crank-shaped RPEL domain forming a closed helical assembly. Their spatial relationship is identical to the RPEL-actins within the pentavalent MRTF G-actin⋅RPEL domain complex, suggesting that conserved cooperative interactions between actin⋅RPEL units organize the assembly. In the trivalent Phactr1 complex, each G-actin⋅RPEL unit makes secondary contacts with its downstream actin involving distinct RPEL residues. Similar secondary contacts are seen in G-actin⋅RPEL peptide crystals. Loss-of-secondary-contact mutations destabilize the Phactr1 G-actin⋅RPEL assembly. Furthermore, actin-mediated inhibition of Phactr1 nuclear import requires secondary contact residues in the Phactr1 N-terminal RPEL-N motif, suggesting that it involves interaction of RPEL-N with the C-terminal assembly. Secondary actin contacts by actin-bound RPEL motifs thus govern formation of multivalent actin⋅RPEL assemblies.