PDBsum entry 1k5o

Protein binding

PDB id: 1k5o

Contents

Protein chain

86 a.a. *

* Residue conservation analysis

PDB id:

1k5o

Name:

Protein binding

Title:

Cpi-17(35-120) deletion mutant

Structure:

Cpi-17. Chain: a. Fragment: residues 1-86. Synonym: 17-kda pkc-potentiated inhibitory protein of pp1. Engineered: yes

Source:

Sus scrofa. Pig. Organism_taxid: 9823. Gene: porcine aorta. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

NMR struc:

1 models

Authors:

S.Ohki,M.Eto,E.Kariya,T.Hayano,Y.Hayashi,M.Yazawa,D.Brautigan, M.Kainosho

Key ref:

S.Ohki et al. (2001). Solution NMR structure of the myosin phosphatase inhibitor protein CPI-17 shows phosphorylation-induced conformational changes responsible for activation. J Mol Biol, 314, 839-849. PubMed id: 11734001 DOI: 10.1006/jmbi.2001.5200

Date:

11-Oct-01 Release date: 11-Oct-02

Protein chain

O18734  (PP14A_PIG) -  Protein phosphatase 1 regulatory subunit 14A from Sus scrofa

Seq: 147 a.a.

Struc: 86 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1006/jmbi.2001.5200

J Mol Biol 314:839-849 (2001)

PubMed id: 11734001

Solution NMR structure of the myosin phosphatase inhibitor protein CPI-17 shows phosphorylation-induced conformational changes responsible for activation.

S.Ohki, M.Eto, E.Kariya, T.Hayano, Y.Hayashi, M.Yazawa, D.Brautigan, M.Kainosho.

ABSTRACT

Contractility of vascular smooth muscle depends on phosphorylation of myosin light chains, and is modulated by hormonal control of myosin phosphatase activity. Signaling pathways activate kinases such as PKC or Rho-dependent kinases that phosphorylate the myosin phosphatase inhibitor protein called CPI-17. Phosphorylation of CPI-17 at Thr38 enhances its inhibitory potency 1000-fold, creating a molecular on/off switch for regulating contraction. We report the solution NMR structure of the CPI-17 inhibitory domain (residues 35-120), which retains the signature biological properties of the full-length protein. The final ensemble of 20 sets of NMR coordinates overlaid onto their mean structure with r.m.s.d. values of 0.84(+/-0.22) A for the backbone atoms. The protein forms a novel four-helix, V-shaped bundle comprised of a central anti-parallel helix pair (B/C helices) flanked by two large spiral loops formed by the N and C termini that are held together by another anti-parallel helix pair (A/D helices) stabilized by intercalated aromatic and aliphatic side-chains. Chemical shift perturbations indicated that phosphorylation of Thr38 induces a conformational change involving displacement of helix A, without significant movement of the other three helices. This conformational change seems to flex one arm of the molecule, thereby exposing new surfaces of the helix A and the nearby phosphorylation loop to form specific interactions with the catalytic site of the phosphatase. This phosphorylation-dependent conformational change offers new structural insights toward understanding the specificity of CPI-17 for myosin phosphatase and its function as a molecular switch.

Selected figure(s)

Figure 3.
Figure 3. The solution NMR structure of CPI-17-[35-120]. (a) Stereo view of the backbone (N, C^a, and C') of 20 superimposed structures. The phosphorylation site T38 is colored orange within the N-terminal region colored yellow. Helices are colored royal-blue. (b) Ribbon representation of an energy-minimized average structure of CPI-17-[35-120]. Helix regions are royal-blue and yellow. The side-chain of Thr38 is depicted by a ball-and-stick model. The first and last residues of each helix are labeled with the residue number and the helices are labeled with upper-case letters. The N-term. and C-term. labels show the positions of the amino and carboxyl ends of the protein, respectively.

Figure 6.
Figure 6. Front and back views of the molecular surface of CPI-17-[35-120] colored according to electrostatic potential. Negative and positive charged areas are colored in red and blue, respectively. Small ribbon models viewed from the identical perspective are drawn at the side of both molecules for orientation. Several amino acid residues are labeled.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2001, 314, 839-849) copyright 2001.

Figures were selected by an automated process.