A CCCH Zinc Finger Conserved in a Replication Protein A Homolog Found in Diverse Euryarchaeotes
| Autor: | Yuyen Lin, Yi Hsing Chen, Ernest K.D. Nyannor, Justin B. Robbins, Isaac K. O. Cann |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
DNA Replication
Archaeal Proteins Molecular Sequence Data Mutant DNA Single-Stranded Genetics and Molecular Biology Euryarchaeota Biology Microbiology Protein structure Replication Protein A Amino Acid Sequence Molecular Biology Replication protein A LIM domain Ions Zinc finger Sp1 transcription factor Alanine Genetic Complementation Test RNA-Binding Proteins Zinc Fingers Zinc finger nuclease Molecular biology RING finger domain Zinc DNA Archaeal Biochemistry Carrier Proteins Sequence Alignment Gene Deletion |
| Zdroj: | Journal of Bacteriology. 187:7881-7889 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.187.23.7881-7889.2005 |
| Popis: | We describe a CCCH type of zinc finger domain in a replication protein A (RPA) homolog found in members of different lineages of the Euryarchaeota , a subdomain of Archaea . The zinc finger is characterized by CX 2 CX 8 CX 2 H, where X is any amino acid. Using MacRPA3, a representative of this new group of RPA in Methanosarcina acetivorans , we made two deletion mutants: a C-terminal deletion mutant lacking the zinc finger and an N-terminal deletion mutant containing the zinc finger domain. Whereas the N-terminal deletion mutant contained zinc at a level comparable to the wild-type protein level, the C-terminal deletion mutant was devoid of zinc. We further created four different mutants of MacRPA3 by replacing each of the four invariable amino acids in the zinc finger with alanine. Each single mutation at an invariable position resulted in a protein containing less than 35% of the zinc found in the wild-type protein. Circular dichroism spectra suggested that although the mutation at the first cysteine resulted in minor perturbation of protein structure, mutations at the other invariable positions led to larger structural changes. All proteins harboring a mutation at one of the invariable positions bound to single-stranded DNA weakly, and this translated into reduced capacity to stimulate DNA synthesis by M. acetivorans DNA polymerase BI. By subjecting the protein and its mutants to oxidizing and reducing conditions, we demonstrated that ssDNA binding by MacRPA3 may be regulated by redox through the zinc finger. Thus, the zinc finger modules in euryarchaeal RPA proteins may serve as a means by which the function of these proteins is regulated in the cell. |
| Databáze: | OpenAIRE |
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