PDBsum entry 1s6j

Transferase, plant protein

PDB id: 1s6j

Contents

Protein chain

87 a.a.

Metals

_CA ×2

References listed in PDB file

Key reference

Title

Solution structure and backbone dynamics of the n-Terminal region of the calcium regulatory domain from soybean calcium-Dependent protein kinase alpha.

Authors

A.M.Weljie, S.M.Gagné, H.J.Vogel.

Ref.

Biochemistry, 2004, 43, 15131-15140. [DOI no: 10.1021/bi048751r]

PubMed id

15568805

Abstract

Ca(2+)-dependent protein kinases (CDPKs) are vital Ca(2+)-signaling proteins in plants and protists which have both a kinase domain and a self-contained calcium regulatory calmodulin-like domain (CLD). Despite being very similar to CaM (>40% identity) and sharing the same fold, recent biochemical and structural evidence suggests that the behavior of CLD is distinct from its namesake, calmodulin. In this study, NMR spectroscopy is employed to examine the structure and backbone dynamics of a 168 amino acid Ca(2+)-saturated construct of the CLD (NtH-CLD) in which almost the entire C-terminal domain is exchange broadened and not visible in the NMR spectra. Structural characterization of the N-terminal domain indicates that the first Ca(2+)-binding loop is significantly more open than in a recently reported structure of the CLD complexed with a putative intramolecular binding region (JD) in the CDPK. Backbone dynamics suggest that parts of the third helix exhibit unusually high mobility, and significant exchange, consistent with previous findings that this helix interacts with the C-terminal domain. Dynamics data also show that the "tether" region, consisting of the first 11 amino acids of CLD, is highly mobile and these residues exhibit distinctive beta-type secondary structure, which may help to position the JD and CLD. Finally, the unusual global dynamic behavior of the protein is rationalized on the basis of possible interdomain rearrangements and the highly variable environments of the C- and N-terminal domains.

Secondary reference #1

Title

Conformational changes in the ca2+-Regulatory region from soybean calcium-Dependent protein kinase-Alpha: fluorescence resonance energy transfer studies.

Authors

A.M.Weljie, K.M.Robertson, H.J.Vogel.

Ref.

J Biol Chem, 2003, 278, 43764-43769. [DOI no: 10.1074/jbc.M306799200]

PubMed id

12941950

Figure 1.
FIG. 1. Schematic diagram of the primary and secondary structure of CLD. The positions of the residues mutated in this study are as indicated. Asterisks indicate the two sites that were labeled with IAEDANS, solid lines denote interdomain distance measurements, and dashed lines denote intradomain measurements. Helices are labeled A-H.

Figure 3.
FIG. 3. Normalized fluorescence emission spectra of wild-type CLD and all mutants used in this study, labeled with IAEDANS in the apo form (A), the Ca^2+-saturated form (B), and with JD peptide present (C) (JD-CLD). Note that although the data cannot be compared quantitatively in this form (without an indication of unlabeled fluorescence), a qualitative idea of the amount of energy transfer can be obtained by contrasting the intensity of the Trp emission peak (near 340 nm) with that of the IAEDANS emission peak (near 470 nm). All spectra were collected with an excitation wavelength of 295 nm.

The above figures are reproduced from the cited reference with permission from the ASBMB

Secondary reference #2

Title

Unexpected structure of the ca2+-Regulatory region from soybean calcium-Dependent protein kinase-Alpha.

Authors

A.M.Weljie, H.J.Vogel.

Ref.

J Biol Chem, 2004, 279, 35494-35502. [DOI no: 10.1074/jbc.M311520200]

PubMed id

15155727

Figure 5.
FIG. 5. Comparison of the activated forms of calmodulin (Protein Data Bank code 1CDM [PDB] , CaM·CaMKII peptide complex), calcineurin B (Protein Data Bank code 1TCO [PDB] ), and the Ca^2+-saturated JD-CLD molecule from this study with the two domains positioned in a manner consistent with FRET-derived distance restraints. The N-terminal domains are shown in red along the y axis.

Figure 6.
FIG. 6. Schematic diagram of JD-CLD interaction. Structural evidence suggests that in the absence of JD peptide there are multiple conformations of the C-terminal lobe, while NMR diffusion and FRET-derived long range data show that the protein is collapsed although not necessarily into a single stable conformation. In this situation, the tether region also has significant flexibility as depicted by the dashed lines. Subsequently the C-terminal lobe of the CLD interacts most significantly on addition of JD peptide to Ca^2+-CLD as the evidence from the current study indicates. The N-terminal lobe likely acts as a scaffold that allows the tether region to position the JD. In the current study where a bimolecular system was used, the tether retains its flexibility, although presumably in the intact protein it would remain less mobile since it is directly attached to the JD. It is not clear to what extent the tether region, linker region, and flexible regions of the C-terminal lobe of the CLD act in concert on binding the JD.

The above figures are reproduced from the cited reference with permission from the ASBMB

Secondary reference #3

Title

A calcium-Dependent protein kinase with a regulatory domain similar to calmodulin.

Authors

J.F.Harper, M.R.Sussman, G.E.Schaller, C.Putnam-Evans, H.Charbonneau, A.C.Harmon.

Ref.

Science, 1991, 252, 951-954. [DOI no: 10.1126/science.1852075]

PubMed id

1852075