2cfm: Difference between revisions

DNA ligases join single-strand breaks in double-stranded DNA, and are, essential to maintain genome integrity in DNA metabolism. Here, we report, the 1.8 A resolution structure of Pyrococcus furiosus DNA ligase (PfuLig), which represents the first full-length atomic view of an ATP-dependent, eukaryotic-type DNA ligase. The enzyme comprises the N-terminal, DNA-binding domain, the middle adenylation domain, and the C-terminal, OB-fold domain. The architecture of each domain resembles those of human, DNA ligase I, but the domain arrangements differ strikingly between the, two enzymes. The closed conformation of the two "catalytic core" domains, at the carboxyl terminus in PfuLig creates a small compartment, which, holds a non-covalently bound AMP molecule. This domain rearrangement, results from the "domain-connecting" role of the helical extension, conserved at the C termini in archaeal and eukaryotic DNA ligases. The DNA, substrate in the human open-ligase is replaced by motif VI in the Pfu, closed-ligase. Both the shapes and electrostatic distributions are similar, between motif VI and the DNA substrate, suggesting that motif VI in the, closed state mimics the incoming substrate DNA. Two basic residues (R531, and K534) in motif VI reside within the active site pocket and interact, with the phosphate group of the bound AMP. The crystallographic and, functional analyses of mutant enzymes revealed that these two residues, within the RxDK sequence play essential and complementary roles in ATP, processing. This sequence is also conserved exclusively among the covalent, nucleotidyltransferases, even including mRNA-capping enzymes with similar, helical extensions at the C termini.

2CFM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pyrococcus_furiosus Pyrococcus furiosus] with MG and AMP as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/DNA_ligase_(ATP) DNA ligase (ATP)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.5.1.1 6.5.1.1] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2CFM OCA].  

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