Replication factor C
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The replication factor C, or RFC, is a five-subunit protein complex that is required for DNA replication.[1][2]
The subunits of this heteropentamer are named Rfc1, Rfc2, Rfc3, Rfc4, and Rfc5 in Saccharomyces cerevisiae. RFC is used in eukaryotic replication as a clamp loader, similar to the γ Complex in Escherichia coli. Its role as a clamp loader involves catalyzing the loading of PCNA onto DNA. It binds to the 3' end of the DNA and uses ATP to open the ring of PCNA so that it can encircle the DNA. ATP hydrolysis causes the release of RFC, with concomitant clamp loading onto DNA. For DNA polymerase, RFC serves as primer identification. RFC plays an important role in the proliferation, invasion, and progression of various malignant tumors. RFC acts as a tumor suppressor gene.
The 5 subunits of replication factor C are
Eukaryotes, yeast, mice, drosophila, calf thymus, humans, rice, and Arabidopsis all contain 5 subunits. There are genes such as 13q12.3-q13, 3q27, and p140 (RFC1), p40 (RFC2), p38 (RFC3), p37 (RFC4), p36 (RFC5) that are located on human chromosomal segments. RFC Boxes (1–8) are the amino acid sequences found in human replication factor C. RFC 1 is the largest RFC subunit, with 8 RFC Boxes. Other RFC subunits have 7 RFC boxes. RFC box 1 has a 90 amino acid-long region, while RFC box 2 is a highly conserved subunit. RFC box 3 includes a phosphate-binding loop. RFC box 5 is the second most conserved box. RFC Box 6 is different between the two subunits such as one large 6a and small 6b subunits.[3]
