Structural studies provide new insights into the role of lysine acetylation on substrate recognition by CARM1 and inform the design of potent peptidomimetic inhibitors

Microbial Biotechnolog

Innate immunity glycoprotein gp-340 variants may modulate human susceptibility to dental caries

<p>Abstract</p> <p>Background</p> <p>Bacterial adhesion is an important determinant of colonization and infection, including dental caries. The salivary scavenger receptor cysteine-rich glycoprotein gp-340, which mediates adhesion of <it>Streptococcus mutans </it>(implicated in caries), harbours three major size variants, designated gp-340 I to III, each specific to an individual saliva. Here we have examined the association of the gp-340 I to III polymorphisms with caries experience and adhesion of <it>S. mutans</it>.</p> <p>Methods</p> <p>A case-referent study was performed in 12-year-old Swedish children with high (n = 19) or low (n = 19) caries experiences. We measured the gp-340 I to III saliva phenotypes and correlated those with multiple outcome measures for caries experience and saliva adhesion of <it>S. mutans </it>using the partial least squares (PLS) multivariate projection technique. In addition, we used traditional statistics and 2-year caries increment to verify the established PLS associations, and bacterial adhesion to purified gp-340 I to III proteins to support possible mechanisms.</p> <p>Results</p> <p>All except one subject were typed as gp-340 I to III (10, 23 and 4, respectively). The gp-340 I phenotype correlated positively with caries experience (VIP = 1.37) and saliva adhesion of <it>S. mutans </it>Ingbritt (VIP = 1.47). The gp-340 II and III phenotypes tended to behave in the opposite way. Moreover, the gp-340 I phenotype tended to show an increased 2-year caries increment compared to phenotypes II/III. Purified gp-340 I protein mediated markedly higher adhesion of <it>S. mutans </it>strains Ingbritt and NG8 and <it>Lactococcus lactis </it>expressing AgI/II adhesins (SpaP or PAc) compared to gp-340 II and III proteins. In addition, the gp-340 I protein appeared over represented in subjects positive for Db, an allelic acidic PRP variant associated with caries, and subjects positive for both gp-340 I and Db tended to experience more caries than those negative for both proteins.</p> <p>Conclusion</p> <p>Gp-340 I behaves as a caries susceptibility protein.</p

Crystallization and Preliminary X-Ray Diffraction Analysis of a Mammal Inositol 1,3,4,5,6-Pentakisphosphate 2-Kinase.

Inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IP5 2-K) is an enzyme that catalyses the formation of phytic acid (IP6) from IP5 and ATP. In mammals, IP6 is involved in multiple events such as DNA repair and mRNA edit and it is the precursor of inositol pyrophosphates, emerging compounds shown to have an essential role in apoptosis. In addition, IP5 2-K have functions in cells independently of its catalytic activity, for example in rRNA biogenesis. We pursue the structure determination of a mammal IP5 2-K by Protein Crystallography. For this purpose, we have designed protocols for recombinant expression and purification of Mus musculus IP5 2-K (mIP5 2-K). The recombinant protein has been expressed in two different hosts, E. coli and insect cells using the LSLt and GST fusion proteins, respectively. Both macromolecule preparations yielded crystals of similar quality. Best crystals diffracted to 4.3 Å (E. coli expression) and 4.0 Å (insect cells expression) maximum resolution. Both type of crystals belong to space group P212121 with an estimated solvent content compatible with the presence of two molecules per asymmetric unit. Gel filtration experiments are in agreement with this enzyme being a monomer. Crystallographic data analysis is currently undergoing.Peer Reviewe

A direct assay for measuring the activity and inhibition of coactivator-associated arginine methyltransferase 1

Coactivator-associated arginine methyltransferase 1 (CARM1) is a member of the family of protein arginine methyltransferases. CARM1 catalyzes methyl group transfer from the cofactor S-adenosyl-L-methionine (AdoMet) to both histone and nonhistone protein substrates. CARM1 is involved in a range of cellular processes, mainly involving RNA transcription and gene regulation. As the aberrant expression of CARM1 has been linked to tumorigenesis, the enzyme is a potential therapeutic target, leading to the development of inhibitors and tool compounds engaging with CARM1. To evaluate the effects of these compounds on the activity of CARM1, sensitive and specific analytical methods are needed. While different methods are currently available to assess the activity of methyltransferases, these assays mainly focus on either the measurement of the cofactor product S-adenosyl-L-homocysteine (AdoHcy) or employ radioactive or expensive reagents, each with their own advantages and limitations. To complement the tools currently available for the analysis of CARM1 activity, we here describe the development of a convenient assay employing peptide substrates derived from poly(A)-binding protein 1 (PABP1). This operationally straightforward liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based approach allows for the direct detection of substrate methylation with minimal workup. The method was validated, and its value in characterizing CARM1 activity and inhibition was demonstrated through a comparative analysis involving a set of established small molecules and peptide-based CARM1 inhibitors

Transition state mimics are valuable mechanistic probes for structural studies with the arginine methyltransferase CARM1

Coactivator associated arginine methyltransferase 1 (CARM1) is a member of the protein arginine methyltransferase (PRMT) family and methylates a range of proteins in eukaryotic cells. Overexpression of CARM1 is implicated in a number of cancers, and it is therefore seen as a potential therapeutic target. Peptide sequences derived from the well-defined CARM1 substrate poly(A)-binding protein 1 (PABP1) were covalently linked to an adenosine moiety as in the AdoMet cofactor to generate transition state mimics. These constructs were found to be potent CARM1 inhibitors and also formed stable complexes with the enzyme. High-resolution crystal structures of CARM1 in complex with these compounds confirm a mode of binding that is indeed reflective of the transition state at the CARM1 active site. Given the transient nature of PRMT–substrate complexes, such transition state mimics represent valuable chemical tools for structural studies aimed at deciphering the regulation of arginine methylation mediated by the family of arginine methyltransferases

Acta Crystallogr D Biol Crystallogr

Protein arginine methyltransferase 7 (PRMT7) is a type III arginine methyltransferase which has been implicated in several biological processes such as transcriptional regulation, DNA damage repair, RNA splicing, cell differentiation and metastasis. PRMT7 is a unique but less characterized member of the family of PRMTs. The crystal structure of full-length PRMT7 from Mus musculus refined at 1.7 A resolution is described. The PRMT7 structure is composed of two catalytic modules in tandem forming a pseudo-dimer and contains only one AdoHcy molecule bound to the N-terminal module. The high-resolution crystal structure presented here revealed several structural features showing that the second active site is frozen in an inactive state by a conserved zinc finger located at the junction between the two PRMT modules and by the collapse of two degenerated AdoMet-binding loops

Functional insights from structural studies of protein arginine methyltransferase 2

FWN – Publicaties zonder aanstelling Universiteit Leide

Acta Crystallogr F Struct Biol Commun

Protein arginine methyltransferase 7 (PRMT7) is a unique but less characterized member of the family of protein arginine methyltransferases (PRMTs) that plays a role in male germline gene imprinting. PRMT7 is the only known PRMT member that catalyzes the monomethylation but not the dimethylation of the target arginine residues and harbours two catalytic domains in tandem. PRMT7 genes from five different species were cloned and expressed in Escherichia coli and Sf21 insect cells. Four gave soluble proteins from Sf21 cells, of which two were homogeneous and one gave crystals. The mouse PRMT7 structure was solved by the single anomalous dispersion method using a crystal soaked with thimerosal that diffracted to beyond 2.1 A resolution. The crystal belonged to space group P4(3)2(1)2, with unit-cell parameters a = b = 97.4, c = 168.1 A and one PRMT7 monomer in the asymmetric unit. The structure of another crystal form belonging to space group I222 was solved by molecular replacement

Rat adrenoleukodystrophy related (ALDR) gene: full-length cDNA sequence and new insight in expression

X-linked adrenoleukodystrophy (X-ALD) is an inherited demyelinating disorder due to mutations in the ALD gene, which encodes a peroxisomal ABC half-transporter (ALDP). It has been suggested that ALDP assembles with ALDRP (adrenoleukodystrophy-related protein), a close homologous half-transporter, to form a functional heterodimer. For the first time full-length ALDRP cDNA (5.5 kb) was cloned, and 5' and 3' RACE analysis revealed that alternative usage of polyadenylation sites generates the two transcripts of 3.0 and 5.5 kb observed in the rat in Northern blot analysis. Southern blotting and chromosomal mapping demonstrated one ALDR locus in the rat genome. Characterisation of the 3' flanking region suggested that an ID sequence might be responsible for high expression of the 5.5 kb ALDRP transcript in rat brain. ALDR gene expression was found to be high in the liver of rats before weaning and very low in adult rats; the reverse developmental regulation was observed in the brain. Fenofibrate, which is a potent inducer of the ALDR gene in the liver of adult rats, could not induce the ALDR gene in suckling rats. The exact significance of this result with regard to development of an efficient pharmacological gene therapy for X-ALD is discussed.Comparative StudyJournal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe