PDBsum entry: 1q8g

Structural protein

PDB id: 1q8g

Contents

Protein chain

166 a.a. *

* Residue conservation analysis

PDB id:

1q8g

Name:

Structural protein

Title:

Nmr structure of human cofilin

Structure:

Cofilin, non-muscle isoform. Chain: a. Synonym: 18 kda phosphoprotein, p18. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: cfl1 or cfl. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

NMR struc:

20 models

Authors:

B.J.Pope,K.M.Zierler-Gould,R.Kuhne,A.G.Weeds,L.J.Ball

Key ref:

B.J.Pope et al. (2004). Solution structure of human cofilin: actin binding, pH sensitivity, and relationship to actin-depolymerizing factor. J Biol Chem, 279, 4840-4848. PubMed id: 14627701 DOI: 10.1074/jbc.M310148200

Date:

21-Aug-03 Release date: 06-Jul-04

Protein chain

P23528  (COF1_HUMAN) -  Cofilin-1

Seq: 166 a.a.

Struc: 166 a.a.

 Gene Ontology (GO) functional annotation 

• Cellular component: intracellular (10 terms)
• Biological process: response to virus (8 terms)
• Biochemical function: protein binding (2 terms)

DOI no: 10.1074/jbc.M310148200

J Biol Chem 279:4840-4848 (2004)

PubMed id: 14627701

Solution structure of human cofilin: actin binding, pH sensitivity, and relationship to actin-depolymerizing factor.

B.J.Pope, K.M.Zierler-Gould, R.Kühne, A.G.Weeds, L.J.Ball.

ABSTRACT

Human actin-depolymerizing factor (ADF) and cofilin are pH-sensitive, actin-depolymerizing proteins. Although 72% identical in sequence, ADF has a much higher depolymerizing activity than cofilin at pH 8. To understand this, we solved the structure of human cofilin using nuclear magnetic resonance and compared it with human ADF. Important sequence differences between vertebrate ADF/cofilins were correlated with unique structural determinants in the F-actin-binding site to account for differences in biochemical activities of the two proteins. Cofilin has a short beta-strand at the C terminus, not found in ADF, which packs against strands beta3/beta4, changing the environment around Lys96, a residue essential for F-actin binding. A salt bridge involving His133 and Asp98 (Glu98 in ADF) may explain the pH sensitivity of human cofilin and ADF; these two residues are fully conserved in vertebrate ADF/cofilins. Chemical shift perturbations identified residues that (i) differ in their chemical environments between wild type cofilin and mutants S3D, which has greatly reduced G-actin binding, and K96Q, which does not bind F-actin; (ii) are affected when G-actin binds cofilin; and (iii) are affected by pH change from 6 to 8. Many residues affected by G-actin binding also show perturbation in the mutants or in response to pH. Our evidence suggests the involvement of residues 133-138 of strand beta5 in all of the activities examined. Because residues in beta5 are perturbed by mutations that affect both G-actin and F-actin binding, this strand forms a "boundary" or "bridge" between the proposed F- and G-actin-binding sites.

Selected figure(s)

Figure 2.
FIG. 2. A and B, ribbon diagrams of the lowest energy structure in two orthogonal orientations. Residues involved in the salt bridge, Asp98 and His133 are labeled in red. The red arrows in A indicate the positions of Ser3 and Lys96, whose mutation affects G-actin and F-actin binding, respectively. C and D, cofilin and ADF, respectively, in similar orientations (-90° rotation of A) to show residues that determine differences between these two vertebrate isoforms. The positions of the main structural elements are marked. Red regions show 68-70, YAT in cofilin and FKH in ADF (i), 143-145, VKD and LNR (ii), 147-149, CTL and 147-148 CI in ADF taking account of the single residue difference between the two proteins (iii), and 157-161, AVISL and 156-160 LIVAF in ADF (iv). The aromatic side chains of Tyr68 (cofilin) and Phe^68 (ADF) are shown in red, whereas His133 and Asp98 (Glu in ADF) are in blue and yellow, respectively. The blue arrowheads show the reduced length of the loop region (residues 47-53) in cofilin.

Figure 4.
FIG. 4. Human cofilin residues showing CSPs in response to mutation K96Q (A), complexation of mutant K96Q with G-actin (B), mutation S3D (D), increased pH on mutant S3D (E), increased pH on w.t. (F). The strongest CSPs are in gold, moderate CSPs are red, and weaker CSPs are in blue. C, residues in K96Q broadened but unshifted in 1:1 complexes with G-actin. Although the mutations have long range effects, their influence is restricted to the half of the protein where the mutation lies. Both point mutations affect residues in 5. G and H, orthogonal views showing residues in K96Q whose NMR signals become broadened (green) or show strong CSPs (gold) upon actin binding. These are mainly located in 4 and 5 in the region centered around Tyr117. The second orientation shows that the actin binding site is asymmetric over the top half of the molecule.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2004, 279, 4840-4848) copyright 2004.

Figures were selected by an automated process.