scholarly journals Comparative analysis reveals adaptive evolution of bat IFITMs and a novel antiviral determinant

2019 ◽  
Author(s):  
Camilla T O Benfield ◽  
Farrell MacKenzie ◽  
Markus Ritzefeld ◽  
Michela Mazzon ◽  
Stuart Weston ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Adaptive Evolution ◽  
Transmembrane Proteins ◽  
Cysteine Residue ◽  
Cysteine Residues ◽  
Restriction Factors ◽  
Emerging Viruses ◽  
Molecular Determinant ◽  
Natural Hosts ◽  
Important Site

ABSTRACTHost interferon-induced transmembrane proteins (IFITMs) are broad-spectrum antiviral restriction factors. Of these, IFITM3 potently inhibits viruses that enter cells through acidic endosomes, many of which are zoonotic and emerging viruses with bats (order Chiroptera) as natural hosts. We previously demonstrated that microbat IFITM3 is antiviral. Here we show that bat IFITMs are characterized by strong adaptive evolution and identify a highly variable and functionally important site - codon 70 - within the conserved CD225 domain of IFITMs. Mutation of this residue in microbat IFITM3 impairs restriction of four different virus families that enter cells via endosomes. This mutant shows altered subcellular localization and reduced S-palmitoylation, a phenotype copied by mutation of conserved cysteine residues in microbat IFITM3. Furthermore, we show that microbat IFITM3 is S-palmitoylated on cysteine residues C71, C72 and C105, mutation of each cysteine residue individually impairs virus restriction, and a triple C71-C72-C105 mutant loses all restriction, concomitant with subcellular re-localization of microbat IFITM3 to Golgi-associated sites. Thus, we propose that S-palmitoylation is critical for Chiropteran IFITM3 function and identify a key molecular determinant of IFITM3 S-palmitoylation.

scholarly journals Bat IFITM3 restriction depends on S-palmitoylation and a polymorphic site within the CD225 domain

2019 ◽  
Vol 3 (1) ◽  
pp. e201900542 ◽  
Author(s):  
Camilla TO Benfield ◽  
Farrell MacKenzie ◽  
Markus Ritzefeld ◽  
Michela Mazzon ◽  
Stuart Weston ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Adaptive Evolution ◽  
Broad Spectrum ◽  
Transmembrane Proteins ◽  
Cysteine Residues ◽  
Restriction Factors ◽  
Emerging Viruses ◽  
Molecular Determinant ◽  
Natural Hosts ◽  
Important Site

Host interferon-induced transmembrane proteins (IFITMs) are broad-spectrum antiviral restriction factors. Of these, IFITM3 potently inhibits viruses that enter cells through acidic endosomes, many of which are zoonotic and emerging viruses with bats (order Chiroptera) as their natural hosts. We previously demonstrated that microbat IFITM3 is antiviral. Here, we show that bat IFITMs are characterized by strong adaptive evolution and identify a highly variable and functionally important site—codon 70—within the conserved CD225 domain of IFITMs. Mutation of this residue in microbat IFITM3 impairs restriction of representatives of four different virus families that enter cells via endosomes. This mutant shows altered subcellular localization and reduced S-palmitoylation, a phenotype copied by mutation of conserved cysteine residues in microbat IFITM3. Furthermore, we show that microbat IFITM3 is S-palmitoylated on cysteine residues C71, C72, and C105, mutation of each cysteine individually impairs virus restriction, and a triple C71A-C72A-C105A mutant loses all restriction activity, concomitant with subcellular re-localization of microbat IFITM3 to Golgi-associated sites. Thus, we propose that S-palmitoylation is critical for Chiropteran IFITM3 function and identify a key molecular determinant of IFITM3 S-palmitoylation.

scholarly journals Foamy Viruses, Bet, and APOBEC3 Restriction

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 504
Author(s):  
Ananda Ayyappan Jaguva Vasudevan ◽  
Daniel Becker ◽  
Tom Luedde ◽  
Holger Gohlke ◽  
Carsten Münk
Keyword(s):  
Current Knowledge ◽  
Regulatory Protein ◽  
Host Population ◽  
Life Cycles ◽  
Restriction Factors ◽  
Host Restriction ◽  
Open Questions ◽  
Foamy Viruses ◽  
Natural Hosts ◽  
Hiv 1

Non-human primates (NHP) are an important source of viruses that can spillover to humans and, after adaptation, spread through the host population. Whereas HIV-1 and HTLV-1 emerged as retroviral pathogens in humans, a unique class of retroviruses called foamy viruses (FV) with zoonotic potential are occasionally detected in bushmeat hunters or zookeepers. Various FVs are endemic in numerous mammalian natural hosts, such as primates, felines, bovines, and equines, and other animals, but not in humans. They are apathogenic, and significant differences exist between the viral life cycles of FV and other retroviruses. Importantly, FVs replicate in the presence of many well-defined retroviral restriction factors such as TRIM5α, BST2 (Tetherin), MX2, and APOBEC3 (A3). While the interaction of A3s with HIV-1 is well studied, the escape mechanisms of FVs from restriction by A3 is much less explored. Here we review the current knowledge of FV biology, host restriction factors, and FV–host interactions with an emphasis on the consequences of FV regulatory protein Bet binding to A3s and outline crucial open questions for future studies.

scholarly journals The Carboxy-Terminal Domain of Glycoprotein N of Human Cytomegalovirus Is Required for Virion Morphogenesis

2007 ◽  
Vol 81 (10) ◽  
pp. 5212-5224 ◽  
Author(s):  
Michael Mach ◽  
Karolina Osinski ◽  
Barbara Kropff ◽  
Ursula Schloetzer-Schrehardt ◽  
Magdalena Krzyzaniak ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Critical Role ◽  
Point Mutations ◽  
Cysteine Residue ◽  
Cysteine Residues ◽  
Type I ◽  
Terminal Domain ◽  
Carboxy Terminal Domain ◽  
Carboxy Terminal ◽  
Assembly Compartment

ABSTRACT Glycoproteins M and N (gM and gN, respectively) are among the few proteins that are conserved across the herpesvirus family. The function of the complex is largely unknown. Whereas deletion from most alphaherpesviruses has marginal effects on the replication of the respective viruses, both proteins are essential for replication of human cytomegalovirus (HCMV). We have constructed a series of mutants in gN to study the function of this protein. gN of HCMV is a type I glycoprotein containing a short carboxy-terminal domain of 14 amino acids, including two cysteine residues directly adjacent to the predicted transmembrane anchor at positions 125 and 126. Deletion of the entire carboxy-terminal domain as well as substitution with the corresponding region from alpha herpesviruses or mutations of both cysteine residues resulted in a replication-incompetent virus. Recombinant viruses containing point mutations of either cysteine residue could be generated. These viruses were profoundly defective for replication. Complex formation of the mutant gNs with gM and transport of the complex to the viral assembly compartment appeared unaltered compared to the wild type. However, in infected cells, large numbers of capsids accumulated in the cytoplasm that failed to acquire an envelope. Transiently expressed gN was shown to be modified by palmitic acid at both cysteine residues. In summary, our data suggest that the carboxy-terminal domain of gN plays a critical role in secondary envelopment of HCMV and that palmitoylation of gN appears to be essential for function in secondary envelopment of HCMV and virus replication.

scholarly journals Identification of persulfide-binding and disulfide-forming cysteine residues in the NifS-like domain of the molybdenum cofactor sulfurase ABA3 by cysteine-scanning mutagenesis

2012 ◽  
Vol 441 (3) ◽  
pp. 823-839 ◽  
Author(s):  
Markus Lehrke ◽  
Steffen Rump ◽  
Torsten Heidenreich ◽  
Josef Wissing ◽  
Ralf R. Mendel ◽  
...  
Keyword(s):  
Structural Model ◽  
Bond Distance ◽  
Aldehyde Oxidase ◽  
Disulfide Bridge ◽  
Cysteine Residue ◽  
Molybdenum Cofactor ◽  
Cysteine Residues ◽  
Xanthine Oxidoreductase ◽  
Cysteine Scanning Mutagenesis ◽  
Molybdenum Cofactor Sulfurase

The Moco (molybdenum cofactor) sulfurase ABA3 from Arabidopsis thaliana catalyses the sulfuration of the Moco of aldehyde oxidase and xanthine oxidoreductase, which represents the final activation step of these enzymes. ABA3 consists of an N-terminal NifS-like domain that exhibits L-cysteine desulfurase activity and a C-terminal domain that binds sulfurated Moco. The strictly conserved Cys430 in the NifS-like domain binds a persulfide intermediate, which is abstracted from the substrate L-cysteine and finally needs to be transferred to the Moco of aldehyde oxidase and xanthine oxidoreductase. In addition to Cys430, another eight cysteine residues are located in the NifS-like domain, with two of them being highly conserved among Moco sulfurase proteins and, at the same time, being in close proximity to Cys430. By determination of the number of surface-exposed cysteine residues and the number of persulfide-binding cysteine residues in combination with the sequential substitution of each of the nine cysteine residues, a second persulfide-binding cysteine residue, Cys206, was identified. Furthermore, the active-site Cys430 was found to be located on top of a loop structure, formed by the two flanking residues Cys428 and Cys435, which are likely to form an intramolecular disulfide bridge. These findings are confirmed by a structural model of the NifS-like domain, which indicates that Cys428 and Cys435 are within disulfide bond distance and that a persulfide transfer from Cys430 to Cys206 is indeed possible.

Modification of a novel x-type high-molecular-weight glutenin subunit gene from Aegilops markgrafii to improve dough strength of wheat flour

2018 ◽  
Vol 69 (9) ◽  
pp. 873
Author(s):  
Xin Ma ◽  
Xuye Du ◽  
Cunyao Bo ◽  
Hongwei Wang ◽  
Anfei Li ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Wheat Flour ◽  
Cysteine Residue ◽  
Site Directed Mutagenesis ◽  
Cysteine Residues ◽  
Dough Strength ◽  
Typical Structure ◽  
Dough Quality

High-molecular-weight glutenin subunits (HMW-GS) in bread wheat are major determinants of dough viscoelastic properties and the end-use quality of wheat flour. Cysteine residues, which form intermolecular disulphide bonds in HMW-GS, could improve the strength of gluten. To our knowledge, the number and position of cysteine residues in HMW-GS are conserved between wheat (Triticum aestivum) and Aegilops markgrafii. In the present study, we modified a gene (1Cx1.1) from Ae. markgrafii for an HMW-GS that possessed the typical structure and conserved number of cysteines. Site-directed mutagenesis was carried out in 1Cx1.1 to investigate how the position of cysteine residues in HMW-GS affects the mixing properties of dough. Six HMW-GS containing an extra cysteine residue were expressed in Escherichia coli, and the proteins were purified at sufficient scale for incorporation into flour to test dough quality. There were large differences in dough property among samples containing different modified subunits. Cysteine substituting in the N-terminal or repetitive-domain of HMW-GS could significantly improve dough quality. The results showed that the strategy was useful for providing genetic resources for gene engineering, and hence could be valuable for improving the processing quality of wheat.

scholarly journals Intra- and Intermolecular Disulfide Bonds of theGP2b Glycoprotein of Equine Arteritis Virus: Relevance forVirus Assembly andInfectivity

2003 ◽  
Vol 77 (24) ◽  
pp. 12996-13004 ◽  
Author(s):  
Roeland Wieringa ◽  
Antoine A. F. de Vries ◽  
Sabine M. Post ◽  
Peter J. M. Rottier
Keyword(s):  
Viral Entry ◽  
Disulfide Bonds ◽  
Rna Virus ◽  
Cysteine Residue ◽  
Envelope Proteins ◽  
Equine Arteritis Virus ◽  
Cysteine Residues ◽  
Virus Infectivity ◽  
Particle Assembly ◽  
Positive Strand Rna

ABSTRACT Equine arteritis virus (EAV) is an enveloped, positive-strand RNA virus belonging to the family Arteriviridae of the order Nidovirales. EAV virions contain six different envelope proteins. The glycoprotein GP5 (previously named GL) and the unglycosylated membrane protein M are the major envelope proteins, while the glycoproteins GP2b (previously named GS), GP3, and GP4 are minor structural proteins. The unglycosylated small hydrophobic envelope protein E is present in virus particles in intermediate molar amounts compared to the other transmembrane proteins. The GP5 and M proteins are both essential for particle assembly. They occur as covalently linked heterodimers that constitute the basic protein matrix of the envelope. The GP2b, GP3, and GP4 proteins occur as a heterotrimeric complex in which disulfide bonds play an important role. The function of this complex has not been established yet, but the available data suggest it to be involved in the viral entry process. Here we investigated the role of the four cysteine residues of the mature GP2b protein in the assembly of the GP2b/GP3/GP4 complex. Open reading frames encoding cysteine-to-serine mutants of the GP2b protein were expressed independently or from a full-length infectious EAV cDNA clone. The results of these experiments support a model in which the cysteine residue at position 102 of GP2b forms an intermolecular cystine bridge with one of the cysteines of the GP4 protein, while the cysteine residues at positions 48 and 137 of GP2b are linked by an intrachain disulfide bond. In this model, another cysteine residue in the GP4 protein is responsible for the covalent association of GP3 with the disulfide-linked GP2b/GP4 heterodimer. In addition, our data highlight the importance of the correct association of the minor EAV envelope glycoproteins for their efficient incorporation into viral particles and for virus infectivity.

scholarly journals CMD: A Database to Store the Bonding States of Cysteine Motifs with Secondary Structures

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Hamed Bostan ◽  
Naomie Salim ◽  
Zeti Azura Hussein ◽  
Peter Klappa ◽  
Mohd Shahir Shamsir
Keyword(s):  
Secondary Structure ◽  
High Throughput Screening ◽  
Laboratory Data ◽  
Cysteine Residue ◽  
Third Party ◽  
Connectivity Pattern ◽  
Cysteine Residues ◽  
Sequence Motif ◽  
Sequence Motifs ◽  
Cysteine Motifs

Computational approaches to the disulphide bonding state and its connectivity pattern prediction are based on various descriptors. One descriptor is the amino acid sequence motifs flanking the cysteine residue motifs. Despite the existence of disulphide bonding information in many databases and applications, there is no complete reference and motif query available at the moment. Cysteine motif database (CMD) is the first online resource that stores all cysteine residues, their flanking motifs with their secondary structure, and propensity values assignment derived from the laboratory data. We extracted more than 3 million cysteine motifs from PDB and UniProt data, annotated with secondary structure assignment, propensity value assignment, and frequency of occurrence and coefficiency of their bonding status. Removal of redundancies generated 15875 unique flanking motifs that are always bonded and 41577 unique patterns that are always nonbonded. Queries are based on the protein ID, FASTA sequence, sequence motif, and secondary structure individually or in batch format using the provided APIs that allow remote users to query our database via third party software and/or high throughput screening/querying. The CMD offers extensive information about the bonded, free cysteine residues, and their motifs that allows in-depth characterization of the sequence motif composition.

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