PDBsum entry 4z94

Protein binding/structural protein

PDB id: 4z94

Contents

Protein chains

371 a.a.

307 a.a.

Ligands

ATP

Metals

_CA ×3

Waters ×182

PDB id:

4z94

Name:

Protein binding/structural protein

Title:

Actin complex with a chimera of tropomodulin-1 and leiomodin-1 actin- binding site 2

Structure:

Actin, alpha skeletal muscle. Chain: a. Synonym: alpha-actin-1. Gelsolin, tropomodulin-1, leiomodin-1 chimera. Chain: g. Fragment: gelsolin residues 12-136 (unp), linker,tropomodulin-1 residues 160-228 (unp), leiomodin-1 actin-binding site 2 (unp residues 364-486). Synonym: agel, actin-depolymerizing factor, adf, brevin,erythrocyte

Source:

Oryctolagus cuniculus. Rabbit. Organism_taxid: 9986. Homo sapiens. Human. Organism_taxid: 9606. Gene: gsn, tmod1, d9s57e, tmod, lmod1. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.40Å R-factor: 0.188 R-free: 0.243

Authors:

G.Rebowski,M.Boczkowska,R.Dominguez

Key ref:

M.Boczkowska et al. (2015). How Leiomodin and Tropomodulin use a common fold for different actin assembly functions. Nat Commun, 6, 8314. PubMed id: 26370058 DOI: 10.1038/ncomms9314

Date:

09-Apr-15 Release date: 21-Oct-15

Protein chain

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

Seq: 377 a.a.

Struc: 371 a.a.*

Protein chain

P06396  (GELS_HUMAN) -  Gelsolin from Homo sapiens

Seq: 782 a.a.

Struc: 307 a.a.*

Protein chain

P28289  (TMOD1_HUMAN) -  Tropomodulin-1 from Homo sapiens

Seq: 359 a.a.

Struc: 307 a.a.*

Protein chain

P29536  (LMOD1_HUMAN) -  Leiomodin-1 from Homo sapiens

Seq: 600 a.a.

Struc: 307 a.a.*

* PDB and UniProt seqs differ at 506 residue positions (black crosses)

Enzyme reactions

• Enzyme class 2: Chain A: E.C.3.6.4.- - ?????
• Enzyme class 3: Chain G: 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.

DOI no: 10.1038/ncomms9314

Nat Commun 6:8314 (2015)

PubMed id: 26370058

How Leiomodin and Tropomodulin use a common fold for different actin assembly functions.

M.Boczkowska, G.Rebowski, E.Kremneva, P.Lappalainen, R.Dominguez.

ABSTRACT

How proteins sharing a common fold have evolved different functions is a fundamental question in biology. Tropomodulins (Tmods) are prototypical actin filament pointed-end-capping proteins, whereas their homologues, Leiomodins (Lmods), are powerful filament nucleators. We show that Tmods and Lmods do not compete biochemically, and display similar but distinct localization in sarcomeres. Changes along the polypeptide chains of Tmods and Lmods exquisitely adapt their functions for capping versus nucleation. Tmods have alternating tropomyosin (TM)- and actin-binding sites (TMBS1, ABS1, TMBS2 and ABS2). Lmods additionally contain a C-terminal extension featuring an actin-binding WH2 domain. Unexpectedly, the different activities of Tmods and Lmods do not arise from the Lmod-specific extension. Instead, nucleation by Lmods depends on two major adaptations-the loss of pointed-end-capping elements present in Tmods and the specialization of the highly conserved ABS2 for recruitment of two or more actin subunits. The WH2 domain plays only an auxiliary role in nucleation.