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N-terminal Regions (n-terminal + regions)
Selected AbstractsThe nonconserved N-terminus of protein phosphatase 2B confers its properties to protein phosphatase 1IUBMB LIFE, Issue 2 2009Xiu-Jie Xie Abstract The protein phosphatase 1 catalytic subunit (PP1c) and the protein phosphatase 2B (PP2B or calcineurin) catalytic subunit (CNA) contain nonconserved N-terminal regions followed by conserved phosphatase cores. To examine the role of the N-termini of these two phosphatases, we substituted the residues 1,8 of PP1c with residues 1,42 of CNA, which is designated CNA(1-42)-PP1(9-330). The activities of CNA(1-42)-PP1(9-330) were similar to those of PP2B and different from those of PP1. The chimera was at least fourfold less sensitive to inhibition by okadaic acid, but was stimulated by nickel ions and chlorogenic acid, characteristics of PP2B not of PP1. These observations suggest that the N-terminus of CNA shifts the properties of PP1 toward those of PP2B. Our findings provide evidence that the nonconserved N-terminus of PP2B not only functions as important regulatory domain but also confers itself particular characteristics. This region may be targeted for regulation of PP2B activities in vivo. © 2008 IUBMB IUBMB Life, 61(2): 178,183, 2009 [source] End-to-end and end-to-middle interhelical interactions: new classes of interacting helix pairs in protein structuresACTA CRYSTALLOGRAPHICA SECTION D, Issue 10 2009Tarini Shankar Ghosh Helix,helix interactions are important for the structure, stability and function of ,-helical proteins. Helices that either cross in the middle or show extensive contacts between each other, such as coiled coils, have been investigated in previous studies. Interactions between two helices can also occur only at the terminal regions or between the terminal region of one helix and the middle region of another helix. Examples of such helix pairs are found in aquaporin, H+/Cl, transporter and Bcl-2 proteins. The frequency of the occurrence of such `end-to-end' (EE) and `end-to-middle' (EM) helix pairs in protein structures is not known. Questions regarding the residue preferences in the interface and the mode of interhelical interactions in such helix pairs also remain unanswered. In this study, high-resolution structures of all-, proteins from the PDB have been systematically analyzed and the helix pairs that interact only in EE or EM fashion have been extracted. EE and EM helix pairs have been categorized into five classes (N,N, N,C, C,C, N,MID and C,MID) depending on the region of interaction. Nearly 13% of 5725 helix pairs belonged to one of the five classes. Analysis of single-residue propensities indicated that hydrophobic and polar residues prefer to occur in the C-terminal and N-terminal regions, respectively. Hydrophobic C-terminal interacting residues and polar N-terminal interacting residues are also highly conserved. A strong correlation exists between some of the residue properties (surface area/volume and length of side chains) and their preferences for occurring in the interface of EE and EM helix pairs. In contrast to interacting non-EE/EM helix pairs, helices in EE and EM pairs are farther apart. In these helix pairs, residues with large surface area/volume and longer side chains are preferred in the interfacial region. [source] Structure of mouse IP-10, a chemokineACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2008Talat Jabeen Interferon-,-inducible protein (IP-10) belongs to the CXC class of chemokines and plays a significant role in the pathophysiology of various immune and inflammatory responses. It is also a potent angiostatic factor with antifibrotic properties. The biological activities of IP-10 are exerted by interactions with the G-protein-coupled receptor CXCR3 expressed on Th1 lymphocytes. IP-10 thus forms an attractive target for structure-based rational drug design of anti-inflammatory molecules. The crystal structure of mouse IP-10 has been determined and reveals a novel tetrameric association. In the tetramer, two conventional CXC chemokine dimers are associated through their N-terminal regions to form a 12-stranded elongated ,-sheet of ,90,Å in length. This association differs significantly from the previously studied tetramers of human IP-10, platelet factor 4 and neutrophil-activating peptide-2. In addition, heparin- and receptor-binding residues were mapped on the surface of IP-10 tetramer. Two heparin-binding sites were observed on the surface and were present at the interface of each of the two ,-sheet dimers. The structure supports the formation of higher order oligomers of IP-10, as observed in recent in vivo studies with mouse IP-10, which will have functional relevance. [source] Crystallographic characterization of the radixin FERM domain bound to the cytoplasmic tail of the adhesion protein ICAM-2ACTA CRYSTALLOGRAPHICA SECTION D, Issue 6 2001Keisuke Hamada Radixin is a member of the ERM proteins, which cross-link plasma membranes and actin filaments. The FERM domains located at the N-terminal regions of ERM proteins are responsible for membrane association through direct interactions with the cytoplasmic domains of integral membrane proteins. Here, crystals of the complex between the radixin FERM domain and the full-length cytoplasmic tail (28-residue peptide) of intercellular adhesion molecule 2, ICAM-2, have been obtained. The crystals were found to belong to space group P3121 or P3221, with unit-cell parameters a = b = 100.44,(9), c = 99.49,(6),Å, and contain one complex in the crystallographic asymmetric unit. An intensity data set was collected to a resolution of 2.60,Å. [source] Crystallographic characterization of the radixin FERM domain bound to the cytoplasmic tails of adhesion molecules CD43 and PSGL-1ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 1 2007Yumiko Takai Radixin is a member of the ERM proteins that cross-link plasma membranes and actin filaments. The FERM domains located in the N-terminal regions of ERM proteins are responsible for membrane association through direct interaction with the cytoplasmic tails of integral membrane proteins. Here, crystals of the radixin FERM domain bound to the cytoplasmic peptides of two adhesion molecules, CD43 and PSGL-1, have been obtained. Crystals of the radixin FERM domain bound to CD43 belong to space group P4322, with unit-cell parameters a = b = 68.72, c = 201.39,Å, and contain one complex in the crystallographic asymmetric unit. Crystals of the radixin FERM domain bound to PSGL-1 belong to space group P212121, with unit-cell parameters a = 80.74, b = 85.73, c = 117.75,Å, and contain two complexes in the crystallographic asymmetric unit. Intensity data sets were collected to a resolution of 2.9,Å for the FERM,CD43 complex and 2.8,Å for the FERM,PSGL-1 complex. [source] | ||||||||||