Structural insights andab initiosequencing within the DING proteins family

Abstract

DING proteins constitute an intriguing family of phosphate-binding proteins that was identified in a wide range of organisms, from prokaryotes and archae to eukaryotes. Despite their seemingly ubiquitous occurrence in eukaryotes, their encoding genes are missing from sequenced genomes. Such a lack has considerably hampered functional studies. In humans, these proteins have been related to several diseases, like atherosclerosis, kidney stones, inflammation processes and HIV inhibition. The human phosphate binding protein is a human representative of the DING family that was serendipitously discovered from human plasma. An original approach was developed to determine ab initio the complete and exact sequence of this 38 kDa protein by utilizing mass spectrometry and X-ray data in tandem. Taking advantage of this first complete eukaryotic DING sequence, a immunohistochemistry study was undertaken to check the presence of DING proteins in various mice tissues, revealing that these proteins are widely expressed. Finally, the structure of a bacterial representative from Pseudomonas fluorescens was solved at sub-angstrom resolution, allowing the molecular mechanism of the phosphate binding in these high-affinity proteins to be elucidated.

Human-Phosphate-Binding-Protein inhibits HIV-1 gene transcription and replication

“…HPBP is a member of the DING protein family identified in eukaryotes for their implication in diverse biological processes [ 28 , 37 ]. Here, we show that the human phosphate binding protein has a potent anti HIV-1 activity.…”

“…More than 40 DING proteins have now been purified, mostly from eukaryotes [[ 27 ] and personal communication] and most of them are associated with biological processes and some diseases [ 28 ]. The ubiquitous presence in eukaryotes of proteins structurally and functionally related to bacterial virulence factors is intriguing, as is the absence of eukaryotic genes encoding DING proteins in databases.…”

Untitled

“…Malgré leur caractère ubiquiste chez les eucaryotes, aucun locus ni ORF (Open Reading Frame ; cadre de lecture ouvert pour la traduction des protéines) n'a été identifié à ce jour dans les génomes eucaryotiques séquencés. Cette particularité a considérablement freiné les études struc-turales et fonctionnelles sur ces protéines, et a nécessité la mise en place de méthodologies innovantes, comme lors du séquençage de l'une de ces protéines par spectrométrie de masse et cristallographie aux rayons X (Elias et al, 2011 ;Chabrière et al, 2012).…”

DING Protein Inhibits Transcription of HIV-1 Gene through Suppression of Phosphorylation of NF-κB p65

“…DING proteins were isolated from animals, plants and prokaryotes, and some are characterized as phosphatases or phosphate-binding proteins [8]. The role of eukaryotic DING proteins on the transcription of HIV-1 LTR has been studied intensively [9][10][11][12][13][14][15][16][17]. Recently, it was determined that DING proteins from phylogenetically different species share similar sequence and structural homology and inhibit HIV-1 LTR transcription [18].…”