PDBsum entry 2igp

Cell cycle

PDB id: 2igp

Contents

Protein chain

114 a.a. *

Ligands

BME ×2

Waters ×72

* Residue conservation analysis

PDB id:

2igp

Name:

Cell cycle

Title:

Crystal structure of hec1 ch domain

Structure:

Retinoblastoma-associated protein hec. Chain: a. Synonym: kinetochore associated 2. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: hec1. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

1.80Å R-factor: 0.201 R-free: 0.231

Authors:

R.R.Wei,S.C.Harrison

Key ref:

R.R.Wei et al. (2007). The Ndc80/HEC1 complex is a contact point for kinetochore-microtubule attachment. Nat Struct Biol, 14, 54-59. PubMed id: 17195848 DOI: 10.1038/nsmb1186

Date:

22-Sep-06 Release date: 02-Jan-07

Protein chain

O14777  (NDC80_HUMAN) -  Kinetochore protein NDC80 homolog from Homo sapiens

Seq: 642 a.a.

Struc: 114 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1038/nsmb1186

Nat Struct Biol 14:54-59 (2007)

PubMed id: 17195848

The Ndc80/HEC1 complex is a contact point for kinetochore-microtubule attachment.

R.R.Wei, J.Al-Bassam, S.C.Harrison.

ABSTRACT

Kinetochores are multicomponent assemblies that connect chromosomal centromeres to mitotic-spindle microtubules. The Ndc80 complex is an essential core element of kinetochores, conserved from yeast to humans. It is a rod-like assembly of four proteins- Ndc80p (HEC1 in humans), Nuf2p, Spc24p and Spc25p. We describe here the crystal structure of the most conserved region of HEC1, which lies at one end of the rod and near the N terminus of the polypeptide chain. It folds into a calponin-homology domain, resembling the microtubule-binding domain of the plus-end-associated protein EB1. We show that an Ndc80p-Nuf2p heterodimer binds microtubules in vitro. The less conserved, N-terminal segment of Ndc80p contributes to the interaction and may be a crucial regulatory element. We propose that the Ndc80 complex forms a direct link between kinetochore core components and spindle microtubules.

Selected figure(s)

Figure 1.
(a) Ribbon diagram of HEC1_CH (HEC[81–196]). (b) View from the opposite direction to a, showing the potential microtubule-binding site, analogous to that on EB1. Side chains of Arg84, Phe125, Tyr160, Phe162 and Tyr187 are shown as sticks. (c) Ribbon diagram of EB1 microtubule-binding domain (PDB 1PA7)^24 in the same orientation as HEC1_CH in a. (d) EB1 microtubule-binding domain, in the same orientation as HEC1_CH in b, showing the proposed microtubule-binding site^24. The side chains of Lys89 and its surrounding hydrophobic residues are shown as sticks, with O and N in red and blue, respectively. N and C termini are labeled.

Figure 2.
(a,b) Surface representations of HEC1_CH in the orientations of Figure 1a,b, respectively, colored by degree of conservation (dark blue, most conserved; white, least conserved), showing that the potential microtubule-binding surface is conserved across species. (c,d) Surface representations showing electrostatic potential of HEC1_CH and EB1 microtubule-binding domain, in the orientations of Figure 1b,d, respectively. Red to blue, -15 k[b]T to +15 k[b]T, as calculated by Delphi^49. (e) Multiple sequence alignment for Ndc80/HEC1 and EB1 CH domain (bottom), generated with CLUSTAL W^50. Secondary structural elements derived from the crystal structure are colored as in Figure 1a. Number of initial residue for each homolog is shown after species name. Residues are colored by degree of conservation: white letters on dark blue background, identical; blue on blue-gray, strongly conserved; light blue on white, weakly conserved. Lys89 of EB1, which is required for microtubule binding, is boxed in red.

The above figures are reprinted by permission from Macmillan Publishers Ltd: Nat Struct Biol (2007, 14, 54-59) copyright 2007.

Figures were selected by an automated process.