scholarly journals Ty3 Nucleocapsid Controls Localization of Particle Assembly

2007 ◽  
Vol 82 (5) ◽  
pp. 2501-2514 ◽  
Author(s):  
Liza S. Z. Larsen ◽  
Nadejda Beliakova-Bethell ◽  
Virginia Bilanchone ◽  
Min Zhang ◽  
Anne Lamsa ◽  
...  
Keyword(s):  
Zinc Binding ◽  
Binding Motif ◽  
Structural Protein ◽  
Rna Packaging ◽  
Particle Assembly ◽  
Conserved Residues ◽  
P Bodies ◽  
Viruslike Particles ◽  
Rna Protection ◽  
Zinc Binding Motif

ABSTRACT Expression of the budding yeast retrotransposon Ty3 results in production of viruslike particles (VLPs) and retrotransposition. The Ty3 major structural protein, Gag3, similar to retrovirus Gag, is processed into capsid, spacer, and nucleocapsid (NC) during VLP maturation. The 57-amino-acid Ty3 NC protein has 17 basic amino acids and contains one copy of the CX2CX4HX4C zinc-binding motif found in retrovirus NC proteins. Ty3 RNA, protein, and VLPs accumulate in clusters associated with RNA processing bodies (P bodies). This study investigated the role of the NC domain in Ty3-P body clustering and VLP assembly. Fifteen Ty3 NC Ala substitution and deletion mutants were examined using transposition, immunoblot, RNA protection, cDNA synthesis, and multimerization assays. Localization of Ty3 proteins and VLPs was characterized microscopically. Substitutions of each of the conserved residues of the zinc-binding motif resulted in the loss of Ty3 RNA packaging. Substitution of the first two of four conserved residues in this motif caused the loss of Ty3 RNA and protein clustering with P bodies and disrupted particle formation. NC was shown to be a mediator of formation of Ty3 RNA foci and association of Ty3 RNA and protein with P bodies. Mutations that disrupted these NC functions resulted in various degrees of Gag3 nuclear localization and a spectrum of different particle states. Our findings are consistent with the model that Ty3 assembly is associated with P-body components. We hypothesize that the NC domain acts as a molecular switch to control Gag3 conformational states that affect both assembly and localization.

scholarly journals First Crystal Structure of a Non-Structural Hepatitis E Viral Protein Identifies a Putative Novel Zinc-Binding Protein

2019 ◽  
Author(s):  
Andrew Proudfoot ◽  
Anastasia Hyrina ◽  
Meghan Holdorf ◽  
Andreas O. Frank ◽  
Dirksen Bussiere
Keyword(s):  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Zinc Binding ◽  
Structural Proteins ◽  
Binding Motif ◽  
Structural Homology ◽  
Structural Protein ◽  
Single Transcript ◽  
Catalytic Zinc ◽  
Zinc Binding Motif

AbstractHepatitis E virus (HEV) is a 7.2 kb positive-sense, single-stranded RNA virus containing three partially overlapping reading frames, ORF 1-3. All non-structural proteins required for viral replication are encoded by ORF1 and are transcribed as a single transcript. Computational analysis of the complete ORF1 polyprotein identified a previously uncharacterized region of predicted secondary structure bordered by two disordered regions coinciding partially with a region predicted as a putative cysteine protease. Following successful cloning, expression and purification of this region, the crystal structure of the identified protein was determined and identified to have considerable structural homology to a fatty acid binding domain. Further analysis of the structure revealed a metal binding site, shown unambiguously to specifically bind zinc via a non-classical, potentially catalytic zinc-binding motif. We present analysis for the first time of this identified non-structural protein, expanding the knowledge and understanding of the complex mechanisms of HEV biology.ImportanceHepatitis E virus (HEV) is an emerging virus found predominately in developing countries causing an estimated 20 million infections, which result in approximately 57,000 deaths a year. Although it is known that the non-structural proteins of the HEV ORF1 are expressed as a single transcript, there is debate as to whether ORF1 functions as a single polyprotein or if it is processed into separate domains via a viral or endogenous cellular protease. In the following paper, we present the first structural and biophysical characterization of a HEV non-structural protein using a construct that has partially overlapping boundaries with the predicted putative cysteine protease. Based on the structural homology of the HEV protein with known structures, along with the presence of a catalytic zinc-binding motif, it is possible that the identified protein corresponds to the HEV protease, which could require activation or repression through the binding of a fatty acid. This represents a significant step forward in the characterization and the understanding of the molecular mechanisms of the HEV genome.

Effect of mutations in a zinc-binding domain of yeast RNA polymerase C (III) on enzyme function and subunit association

1992 ◽  
Vol 12 (3) ◽  
pp. 1087-1095
Author(s):  
M Werner ◽  
S Hermann-Le Denmat ◽  
I Treich ◽  
A Sentenac ◽  
P Thuriaux
Keyword(s):  
Rna Polymerase ◽  
Zinc Binding ◽  
Enzyme Function ◽  
Directed Mutagenesis ◽  
Binding Motif ◽  
Zinc Ions ◽  
Amino Terminal ◽  
Zinc Binding Domain ◽  
Zinc Binding Motif

The conserved amino-terminal region of the largest subunit of yeast RNA polymerase C is capable of binding zinc ions in vitro. By oligonucleotide-directed mutagenesis, we show that the putative zinc-binding motif CX2CX6-12CXGHXGX24-37CX2C, present in the largest subunit of all eukaryotic and archaebacterial RNA polymerases, is essential for the function of RNA polymerase C. All mutations in the invariant cysteine and histidine residues conferred a lethal phenotype. We also obtained two conditional thermosensitive mutants affecting this region. One of these produced a form of RNA polymerase C which was thermosensitive and unstable in vitro. This instability was correlated with the loss of three of the subunits which are specific to RNA polymerase C: C82, C34, and C31.

scholarly journals Phosphonamidates are the first phosphorus-based zinc binding motif to show inhibition of β-class carbonic anhydrases from bacteria, fungi, and protozoa

2019 ◽  
Vol 35 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Siham A. Alissa ◽  
Hanan A. Alghulikah ◽  
Zeid A. Alothman ◽  
Sameh M. Osman ◽  
Sonia Del Prete ◽  
...  
Keyword(s):  
Zinc Binding ◽  
Binding Motif ◽  
Carbonic Anhydrases ◽  
Zinc Binding Motif

Conformational dynamics and allosteric effect modulated by the unique zinc-binding motif in class IIa HDACs

2019 ◽  
Vol 21 (23) ◽  
pp. 12173-12183 ◽  
Author(s):  
Huawei Liu ◽  
Fan Zhang ◽  
Kai Wang ◽  
Xiaowen Tang ◽  
Ruibo Wu
Keyword(s):  
Histone Deacetylases ◽  
Conformational Dynamics ◽  
Zinc Binding ◽  
Binding Motif ◽  
Allosteric Effect ◽  
Class Iia Hdacs ◽  
Zinc Binding Motif

Class IIa histone deacetylases (HDACs) have been considered as potential targets for the treatment of several diseases.

scholarly journals Effect of mutations in a zinc-binding domain of yeast RNA polymerase C (III) on enzyme function and subunit association.

1992 ◽  
Vol 12 (3) ◽  
pp. 1087-1095 ◽  
Author(s):  
M Werner ◽  
S Hermann-Le Denmat ◽  
I Treich ◽  
A Sentenac ◽  
P Thuriaux
Keyword(s):  
Rna Polymerase ◽  
Zinc Binding ◽  
Enzyme Function ◽  
Directed Mutagenesis ◽  
Binding Motif ◽  
Zinc Ions ◽  
Amino Terminal ◽  
Zinc Binding Domain ◽  
Zinc Binding Motif

The conserved amino-terminal region of the largest subunit of yeast RNA polymerase C is capable of binding zinc ions in vitro. By oligonucleotide-directed mutagenesis, we show that the putative zinc-binding motif CX2CX6-12CXGHXGX24-37CX2C, present in the largest subunit of all eukaryotic and archaebacterial RNA polymerases, is essential for the function of RNA polymerase C. All mutations in the invariant cysteine and histidine residues conferred a lethal phenotype. We also obtained two conditional thermosensitive mutants affecting this region. One of these produced a form of RNA polymerase C which was thermosensitive and unstable in vitro. This instability was correlated with the loss of three of the subunits which are specific to RNA polymerase C: C82, C34, and C31.

scholarly journals Mutational analysis of the proteolytic domain of pregnancy-associated plasma protein-A (PAPP-A): classification as a metzincin

2001 ◽  
Vol 358 (2) ◽  
pp. 359-367 ◽  
Author(s):  
Henning B. BOLDT ◽  
Michael T. OVERGAARD ◽  
Lisbeth S. LAURSEN ◽  
Kathrin WEYER ◽  
Lars SOTTRUP-JENSEN ◽  
...  
Keyword(s):  
Plasma Protein ◽  
Active Site ◽  
Mammalian Cells ◽  
Mutational Analysis ◽  
Protein A ◽  
Residual Activity ◽  
Zinc Binding ◽  
Binding Motif ◽  
Dependent Manner ◽  
Zinc Binding Motif

The bioavailability of insulin-like growth factor (IGF)-I and -II is controlled by six IGF-binding proteins (IGFBPs 1–6). Bound IGF is not active, but proteolytic cleavage of the binding protein causes release of IGF. Pregnancy-associated plasma protein-A (PAPP-A) has recently been found to cleave IGFBP-4 in an IGF-dependent manner. To experimentally support the hypothesis that PAPP-A belongs to the metzincin superfamily of metalloproteinases, all containing the elongated zinc-binding motif HEXXHXXGXXH (His-482–His-492 in PAPP-A), we expressed mutants of PAPP-A in mammalian cells. Substitution of Glu-483 with Ala causes a complete loss of activity, defining this motif as part of the active site of PAPP-A. Interestingly, a mutant with Glu-483 replaced by Gln shows residual activity. Known metzincin structures contain a so-called Met-turn, whose strictly conserved Met residue is thought to interact directly with residues of the active site. By further mutagenesis we provide experimental evidence that Met-556 of PAPP-A, 63 residues from the zinc-binding motif, is located in a Met-turn of PAPP-A. Our hypothesis is also supported by secondary-structure prediction, and the ability of a 55-residue deletion mutant (d[S498-Y552]) to express and retain antigenecity. However, because PAPP-A differs in the features defining the individual established metzincin families, we suggest that PAPP-A belongs to a separate family. We also found that PAPP-A can undergo autocleavage, and that autocleaved PAPP-A is inactive. A lack of unifying elements in the sequences around the found cleavage sites of PAPP-A and a variant suggests steric regulation of substrate specificity.

COP1, an arabidopsis regulatory gene, encodes a protein with both a zinc-binding motif and a Gβ homologous domain

Cell ◽  
1992 ◽  
Vol 71 (5) ◽  
pp. 791-801 ◽  
Author(s):  
Xing-Wang Deng ◽  
Minami Matsui ◽  
Ning Wei ◽  
Doris Wagner ◽  
Angela M. Chu ◽  
...  
Keyword(s):  
Regulatory Gene ◽  
Zinc Binding ◽  
Binding Motif ◽  
Zinc Binding Motif

scholarly journals The zinc-binding motif of human RECQ5β suppresses the intrinsic strand-annealing activity of its DExH helicase domain and is essential for the helicase activity of the enzyme

2008 ◽  
Vol 412 (3) ◽  
pp. 425-433 ◽  
Author(s):  
Hua Ren ◽  
Shuo-Xing Dou ◽  
Xing-Dong Zhang ◽  
Peng-Ye Wang ◽  
Radhakrishnan Kanagaraj ◽  
...  
Keyword(s):  
Structural Similarity ◽  
Zinc Binding ◽  
Binding Motif ◽  
Dna Unwinding ◽  
Helicase Domain ◽  
The Novel ◽  
Quantitative Measurements ◽  
Strand Annealing ◽  
Zinc Binding Motif

RecQ family helicases, functioning as caretakers of genomic integrity, contain a zinc-binding motif which is highly conserved among these helicases, but does not have a substantial structural similarity with any other known zinc-finger folds. In the present study, we show that a truncated variant of the human RECQ5β helicase comprised of the conserved helicase domain only, a splice variant named RECQ5α, possesses neither ATPase nor DNA-unwinding activities, but surprisingly displays a strong strand-annealing activity. In contrast, fragments of RECQ5β including the intact zinc-binding motif, which is located immediately downstream of the helicase domain, exhibit much reduced strand-annealing activity but are proficient in DNA unwinding. Quantitative measurements indicate that the regulatory role of the zinc-binding motif is achieved by enhancing the DNA-binding affinity of the enzyme. The novel intramolecular modulation of RECQ5β catalytic activity mediated by the zinc-binding motif may represent a universal regulation mode for all RecQ family helicases.

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