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Irákleion, Greece

Wilhelmus S.,Leiden University | Bajema I.M.,Leiden University | Bertsias G.K.,University of Crete | Boumpas D.T.,IMBB FORTH | And 5 more authors.
Nephrology Dialysis Transplantation | Year: 2016

In the past years, many (randomized) trials have been performed comparing the treatment strategies for lupus nephritis. In 2012, these data were incorporated in six different guidelines for treating lupus nephritis. These guidelines are European, American and internationally based, with one separate guideline for children. They offer information on different aspects of the management of lupus nephritis including induction and maintenance treatment of the different histological classes, adjunctive treatment, monitoring of the patient, definitions of response and relapse, indications for (repeat) renal biopsy, and additional challenges such as the presence of vascular complications, the pregnant SLE patient, treatment in children and adolescents and considerations about end-stage renal disease and transplantation. In this review, we summarize the guidelines, determine the common ground between them, highlight the differences and discuss recent literature. © 2015 The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Gessmann R.,IMBB FORTH | Kyvelidou C.,University of Crete | Papadovasilaki M.,IMBB FORTH | Petratos K.,IMBB FORTH
Biopolymers | Year: 2011

The Cu(II) center at the active site of the blue copper protein pseudoazurin from Alcaligenes faecalis has been substituted by Co(II) via denaturing of the protein, chelation and removal of copper by EDTA and refolding of the apo-protein, followed by addition of an aqueous solution of CoCl 2. Sitting drop vapour diffusion experiments produced green hexagonal crystals, which belong to space group P65, with unit cell dimensions a = b = 50.03, c = 98.80 Å Diffraction data, collected at 291 K on a copper rotating anode X-ray source, were phased by the anomalous signal of the cobalt atom. The structure was built automatically, fitted manually and subsequently refined to 1.86 Å resolution. The Co-substituted protein exhibits similar overall geometry to the native structure with copper. Cobalt binds more strongly to the axial Met86-Sδ and retains the tetrahedral arrangement with the four ligand atoms, His40-Nδ1, Cys78-SIγ, His81-Nδ1, and 86Met-Sδ, although the structure is less distorted than the native copper protein. The structure reported herein, is the first crystallographic structure of a Co(II)-substituted pseudoazurin. © 2010 Wiley Periodicals, Inc.

Gessmann R.,IMBB FORTH | Axford D.,Diamond Light Source | Owen R.L.,Diamond Light Source | Bruckner H.,Justus Liebig University | And 2 more authors.
Acta Crystallographica Section D: Biological Crystallography | Year: 2012

The first crystal structure of a member of peptaibol antibiotic subfamily 4, trichovirin I-4A (14 residues), has been determined by direct methods and refined at atomic resolution. The monoclinic unit cell has two molecules in the asymmetric unit. Both molecules assume a 3 10 right-handed helical conformation and are significantly bent. The molecules pack loosely along the crystallographic twofold axis, forming two large tunnels between symmetry-related molecules in which no ordered solvent could be located. Carbonyl O atoms which are not involved in intramolecular hydrogen bonding participate in close van der Waals interactions with apolar groups. The necessary amphipathicity for biological activity of peptaibols is not realised in the crystal structure. Hence, a structural change of trichovirin to an α-helical conformation is proposed for membrane integration and efficient water/ion transportation across the lipid bilayer. © 2012 International Union of Crystallography.

Gessmann R.,IMBB FORTH | Axford D.,Diamond Light Source | Evans G.,Diamond Light Source | Bruckner H.,Justus Liebig University | And 2 more authors.
Journal of Peptide Science | Year: 2012

The atomic resolution structures of samarosporin I have been determined at 100 and 293K. This is the first crystal structure of a natural 15-residue peptaibol. The amino acid sequence in samarosporin I is identical to emerimicin IV and stilbellin I. Samarosporin is a peptide antibiotic produced by the ascomycetous fungus Samarospora rostrup and belongs to peptaibol subfamily 2. The structures at both temperatures are very similar to each other adopting mainly a 310-helical and a minor fraction of α-helical conformation. The helices are significantly bent and packed in an antiparallel fashion in the centered monoclinic lattice leaving among them an approximately 10-Å channel extending along the crystallographic twofold axis. Only two ordered water molecules per peptide molecule were located in the channel. Comparisons have been carried out with crystal structures of subfamily 2 16-residue peptaibols antiamoebin and cephaibols. The repercussion of the structural analysis of samarosporin on membrane function is discussed. © 2012 European Peptide Society and John Wiley & Sons, Ltd.

Gessmann R.,IMBB FORTH | Bruckner H.,Justus Liebig University | Petratos K.,IMBB FORTH
Acta Crystallographica Section C: Structural Chemistry | Year: 2014

The title peptide, N-benzyloxycarbonyl-α-aminoisobutyryl-α- aminoisobutyryl-α-aminoisobutyryl-l-alanine tert-butyl ester or Z-Aib-Aib-Aib-l-Ala-OtBu (Aib is α-aminoisobutyric acid, Z is benzyloxycarbonyl and OtBu indicates the tert-butyl ester), C27H 42N4O7, is a left-handed helix with a right-handed conformation in the fourth residue, which is the only chiral residue. There are two 4→1 intramolecular hydrogen bonds in the structure. In the lattice, molecules are hydrogen bonded to form columns along the c axis. © 2014 International Union of Crystallography.

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