PDBsum entry: 1bkr

Actin-binding

PDB id: 1bkr

Contents

Protein chain

108 a.a. *

Waters ×208

* Residue conservation analysis

PDB id:

1bkr

Name:

Actin-binding

Title:

Calponin homology (ch) domain from human beta-spectrin at 1.1 angstrom resolution

Structure:

Spectrin beta chain. Chain: a. Fragment: f-actin binding domain residues 173 - 281. Synonym: calponin homology (ch) domain. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Cell: non-erythrocyte. Cellular_location: cytoskeletal protein. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.

Resolution:

1.10Å R-factor: 0.141 R-free: 0.187

Authors:

K.Djinovic Carugo,S.Banuelos,M.Saraste

Key ref:

S.Bañuelos et al. (1998). Structural comparisons of calponin homology domains: implications for actin binding. Structure, 6, 1419-1431. PubMed id: 9817844 DOI: 10.1016/S0969-2126(98)00141-5

Date:

10-Jul-98 Release date: 15-Jul-98

Protein chain

Q01082  (SPTB2_HUMAN) -  Spectrin beta chain, brain 1

Seq: 2364 a.a.

Struc: 108 a.a.

DOI no: 10.1016/S0969-2126(98)00141-5

Structure 6:1419-1431 (1998)

PubMed id: 9817844

Structural comparisons of calponin homology domains: implications for actin binding.

S.Bañuelos, M.Saraste, K.D.Carugo.

ABSTRACT

BACKGROUND: The actin-binding site of several cytoskeletal proteins is comprised of two calponin homology (CH) domains in a tandem arrangement. As a single copy, the CH domain is also found in regulatory proteins in muscle and in signal-transduction proteins. The three-dimensional structures of three CH domains are known, but they have not yet clarified the molecular details of the interaction between actin filaments and proteins harbouring CH domains. RESULTS: We have compared the crystal structure of a CH domain from beta-spectrin, which has been refined to 1.1 A resolution, with the two CH domains that constitute the actin-binding region of fimbrin. This analysis has allowed the construction of a structure-based sequence alignment of CH domains that can be used in further comparisons of members of the CH domain family. The study has also improved our understanding of the factors that determine domain architecture, and has led to discussion on the functional differences that seem to exist between subfamilies of CH domains, as regards binding to F-actin. CONCLUSIONS: Our analysis supports biochemical data that implicate a surface centered at the last helix of the N-terminal CH domain as the most probable actin-binding site in cytoskeletal proteins. It is not clear whether the C-terminal domains of the tandem arrangement or the single CH domains have this function alone. This may imply that although the CH domains are homologous and have a conserved structure, they may have evolved to perform different functions.

Selected figure(s)

Figure 6.
Figure 6. The structure of the actin-binding region of fimbrin and the interface between the CH1 and CH2 domains. The protein backbone is shown as a ribbon; sidechains of residues discussed in the text are shown in ball-and-stick representation. The colour coding ramps from blue (for N-terminal residues) to red (for C-terminal residues). (a) Ribbon representation of the actin-binding region of fimbrin. (b) Close-up stereoview of the region involved at the intersubunit interface. (The figure was made using the program MOLSCRIPT [47].)

The above figure is reprinted by permission from Cell Press: Structure (1998, 6, 1419-1431) copyright 1998.

Figure was selected by an automated process.