scholarly journals A Phage Single-Stranded DNA (ssDNA) Binding Protein Complements ssDNA Accumulation of a Geminivirus and Interferes with Viral Movement

1999 ◽  
Vol 73 (2) ◽  
pp. 1609-1616 ◽  
Author(s):  
Malla Padidam ◽  
Roger N. Beachy ◽  
Claude M. Fauquet
Keyword(s):  
Binding Protein ◽  
Systemic Infection ◽  
Plant Viruses ◽  
Wild Type Virus ◽  
Wild Type ◽  
Direct Role ◽  
Single Stranded Dna ◽  
Ssdna Binding ◽  
Ssdna Binding Protein ◽  
Tomato Leaf Curl

ABSTRACT Geminiviruses are plant viruses with circular single-stranded DNA (ssDNA) genomes encapsidated in double icosahedral particles. Tomato leaf curl geminivirus (ToLCV) requires coat protein (CP) for the accumulation of ssDNA in protoplasts and in plants but not for systemic infection and symptom development in plants. In the absence of CP, infected protoplasts accumulate reduced levels of ssDNA and increased amounts of double-stranded DNA (dsDNA), compared to accumulation in the presence of wild-type virus. To determine whether the gene 5 protein (g5p), a ssDNA binding protein from Escherichia coli phage M13, could restore the accumulation of ssDNA, ToLCV that lacked the CP gene was modified to express g5p or g5p fused to the N-terminal 66 amino acids of CP (CP66:6G:g5). The modified viruses led to the accumulation of wild-type levels of ssDNA and high levels of dsDNA. The accumulation of ssDNA was apparently due to stable binding of g5p to viral ssDNA. The high levels of dsDNA accumulation during infections with the modified viruses suggested a direct role for CP in viral DNA replication. ToLCV that produced the CP66:6G:g5 protein did not spread efficiently in Nicotiana benthamiana plants, and inoculated plants developed only very mild symptoms. In infected protoplasts, the CP66:6G:g5 protein was immunolocalized to nuclei. We propose that the fusion protein interferes with the function of the BV1 movement protein and thereby prevents spread of the infection.

scholarly journals Identification of the mouse low-salt-eluting single-stranded DNA-binding protein as a mammalian lactate dehydrogenase-A isoenzyme

1986 ◽  
Vol 233 (3) ◽  
pp. 913-916 ◽  
Author(s):  
F S Sharief ◽  
S H Wilson ◽  
S S-L Li
Keyword(s):  
Lactate Dehydrogenase ◽  
Binding Protein ◽  
Rabbit Antiserum ◽  
Single Stranded Dna ◽  
Ssdna Binding ◽  
Low Salt ◽  
Ssdna Binding Protein ◽  
A Subunit ◽  
Cellulose Column ◽  
Mouse Myeloma

A 36,000-Mr protein purified from mouse myeloma on the basis of selective binding to a single-stranded DNA (ssDNA)-cellulose column has been identified as the lactate dehydrogenase A (LDH-A) subunit. A homogeneous preparation of this mouse myeloma ssDNA-binding protein, termed the ‘low-salt-eluting protein’, was found to possess LDH activity, and rabbit antiserum prepared against this protein was shown to cross-react with purified 36,000-Mr LDH-A subunits from mouse and bovine sources. In addition, bovine and human LHD-A4 isoenzymes were shown to be capable of binding ssDNA. These enzymic and immunological identities with LDH-A were not observed with purified helix-destabilizing protein 1 from mouse myeloma. A model for ssDNA-LDH binding is discussed.

Tolerance to tomato leaf curl New Delhi begomovirus in transgenic Nicotiana benthamiana expressing the phage M13 gene 5 (G5), an ssDNA binding protein

2020 ◽  
Vol 45 (4) ◽  
pp. 443-447
Author(s):  
Ghulam Rasool ◽  
Sumaira Yousaf ◽  
Afzal Akram ◽  
Shahid Mansoor ◽  
Rob W. Briddon ◽  
...  
Keyword(s):  
Nicotiana Benthamiana ◽  
Binding Protein ◽  
Tomato Leaf ◽  
New Delhi ◽  
Ssdna Binding ◽  
Ssdna Binding Protein ◽  
Tomato Leaf Curl ◽  
Leaf Curl

scholarly journals A Complexed Crystal Structure of a Single-Stranded DNA-Binding Protein with Quercetin and the Structural Basis of Flavonol Inhibition Specificity

2022 ◽  
Vol 23 (2) ◽  
pp. 588
Author(s):  
En-Shyh Lin ◽  
Ren-Hong Luo ◽  
Cheng-Yang Huang
Keyword(s):  
Crystal Structure ◽  
Binding Protein ◽  
Binding Activity ◽  
Structural Basis ◽  
Molecular Evidence ◽  
Mobility Shift ◽  
Single Stranded Dna ◽  
Ssdna Binding ◽  
Replacement Method ◽  
Ssdna Binding Protein

Single-stranded DNA (ssDNA)-binding protein (SSB) plays a crucial role in DNA replication, repair, and recombination as well as replication fork restarts. SSB is essential for cell survival and, thus, is an attractive target for potential antipathogen chemotherapy. Whether naturally occurring products can inhibit SSB remains unknown. In this study, the effect of the flavonols myricetin, quercetin, kaempferol, and galangin on the inhibition of Pseudomonas aeruginosa SSB (PaSSB) was investigated. Furthermore, SSB was identified as a novel quercetin-binding protein. Through an electrophoretic mobility shift analysis, myricetin could inhibit the ssDNA binding activity of PaSSB with an IC50 of 2.8 ± 0.4 μM. The effect of quercetin, kaempferol, and galangin was insignificant. To elucidate the flavonol inhibition specificity, the crystal structure of PaSSB complexed with the non-inhibitor quercetin was solved using the molecular replacement method at a resolution of 2.3 Å (PDB entry 7VUM) and compared with a structure with the inhibitor myricetin (PDB entry 5YUN). Although myricetin and quercetin bound PaSSB at a similar site, their binding poses were different. Compared with myricetin, the aromatic ring of quercetin shifted by a distance of 4.9 Å and an angle of 31o for hydrogen bonding to the side chain of Asn108 in PaSSB. In addition, myricetin occupied and interacted with the ssDNA binding sites Lys7 and Glu80 in PaSSB whereas quercetin did not. This result might explain why myricetin could, but quercetin could not, strongly inhibit PaSSB. This molecular evidence reveals the flavonol inhibition specificity and also extends the interactomes of the natural anticancer products myricetin and quercetin to include the OB-fold protein SSB.

scholarly journals Insight into the dynamics of APOBEC3G protein in complexes with DNA assessed by high speed AFM

2019 ◽  
Vol 1 (10) ◽  
pp. 4016-4024 ◽  
Author(s):  
Yangang Pan ◽  
Luda S. Shlyakhtenko ◽  
Yuri L. Lyubchenko
Keyword(s):  
Reverse Transcription ◽  
Viral Genome ◽  
High Speed ◽  
Binding Protein ◽  
Single Stranded Dna ◽  
Ssdna Binding ◽  
Hiv Virus ◽  
Ssdna Binding Protein ◽  
Insight Into

APOBEC3G (A3G) is a single-stranded DNA (ssDNA) binding protein that restricts the HIV virus by deamination of dC to dU during reverse transcription of the viral genome.

scholarly journals The Bloom syndrome complex senses RPA-coated single-stranded DNA to restart stalled replication forks

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ann-Marie K. Shorrocks ◽  
Samuel E. Jones ◽  
Kaima Tsukada ◽  
Carl A. Morrow ◽  
Zoulikha Belblidia ◽  
...  
Keyword(s):  
Replication Stress ◽  
Bloom Syndrome ◽  
Holliday Junctions ◽  
Replication Forks ◽  
Single Stranded Dna ◽  
Ssdna Binding ◽  
Ssdna Binding Protein ◽  
Dna Replication Stress ◽  
Dna End Resection ◽  
Stalled Replication Forks

AbstractThe Bloom syndrome helicase BLM interacts with topoisomerase IIIα (TOP3A), RMI1 and RMI2 to form the BTR complex, which dissolves double Holliday junctions to produce non-crossover homologous recombination (HR) products. BLM also promotes DNA-end resection, restart of stalled replication forks, and processing of ultra-fine DNA bridges in mitosis. How these activities of the BTR complex are regulated in cells is still unclear. Here, we identify multiple conserved motifs within the BTR complex that interact cooperatively with the single-stranded DNA (ssDNA)-binding protein RPA. Furthermore, we demonstrate that RPA-binding is required for stable BLM recruitment to sites of DNA replication stress and for fork restart, but not for its roles in HR or mitosis. Our findings suggest a model in which the BTR complex contains the intrinsic ability to sense levels of RPA-ssDNA at replication forks, which controls BLM recruitment and activation in response to replication stress.

scholarly journals The AC4 Protein of a Cassava Geminivirus Is Required for Virus Infection

2019 ◽  
Vol 32 (7) ◽  
pp. 865-875 ◽  
Author(s):  
Kegui Chen ◽  
Behnam Khatabi ◽  
Vincent N. Fondong
Keyword(s):  
Plant Viruses ◽  
Wild Type Virus ◽  
Virus Infectivity ◽  
Type Virus ◽  
Wild Type ◽  
Knockout Mutant ◽  
East African ◽  
Reading Frame ◽  
Cell Membrane Binding

Geminiviruses (family Geminiviridae) are among the most devastating plant viruses worldwide, causing severe damage in crops of economic and subsistence importance. These viruses have very compact genomes and many of the encoded proteins are multifunctional. Here, we investigated the role of the East African cassava mosaic Cameroon virus (EACMCV) AC4 on virus infectivity in Nicotiana benthamiana. Results showed that plants inoculated with EACMCV containing a knockout mutation in an AC4 open reading frame displayed symptoms 2 to 3 days later than plants inoculated with wild-type virus, and these plants recovered from infection, whereas plants inoculated with the wild-type virus did not. Curiously, when an additional mutation was made in the knockout mutant, the resulting double mutant virus completely failed to cause any apparent symptoms. Interestingly, the role of AC4 on virus infectivity appeared to be dependent on an encoded N-myristoylation motif that mediates cell membrane binding. We previously showed that EACMCV containing the AC4T38I mutant produced virus progeny characterized by second-site mutations and reversion to wild-type virus. These results were confirmed in this study using additional mutations. Together, these results show involvement of EACMCV AC4 in virus infectivity; they also suggest a role for the combined action of mutation and selection, under prevailing environmental conditions, on begomovirus genetic variation and diversity.

Sign in / Sign up

Export Citation Format

Share Document