1olo
From Proteopedia
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==Overview== | ==Overview== | ||
| - | In the known monoclinic crystals the 3-dimensional structure of the, hexameric, replicative helicase RepA encoded by plasmid RSF1010 shows, 6-fold rotational symmetry. In contrast, in the cubic crystal form at 2.55, A resolution described here RepA has 3-fold symmetry and consists of a, trimer of dimers. To study structure-function relationships, a series of, repA deletion mutants and mutations yielding single amino acid exchanges, were constructed and the respective gene products were analyzed in vivo, and in vitro. Hexamerization of RepA occurs via the N-terminus and is, required for NTP hydrolysis. The C-terminus is essential both for the, interaction with the replication machinery and for the helicase activity., Functional analyses of RepA variants with single amino acid exchanges, ... | + | In the known monoclinic crystals the 3-dimensional structure of the, hexameric, replicative helicase RepA encoded by plasmid RSF1010 shows, 6-fold rotational symmetry. In contrast, in the cubic crystal form at 2.55, A resolution described here RepA has 3-fold symmetry and consists of a, trimer of dimers. To study structure-function relationships, a series of, repA deletion mutants and mutations yielding single amino acid exchanges, were constructed and the respective gene products were analyzed in vivo, and in vitro. Hexamerization of RepA occurs via the N-terminus and is, required for NTP hydrolysis. The C-terminus is essential both for the, interaction with the replication machinery and for the helicase activity., Functional analyses of RepA variants with single amino acid exchanges, confirmed most of the predictions that were based on the published, 3-dimensional structure. Of the five motifs conserved in family 4, helicases, all residues conserved in RepA and T7 gp4 helicases participate, in DNA unwinding. Residues K42, E76, D77, D139 and H178, proposed to play, key roles in catalyzing the hydrolysis of NTPs, are essential for RepA, activity. Residue H178 of motif H3 couples nucleotide consumption to DNA, strand separation. |
==About this Structure== | ==About this Structure== | ||
| - | 1OLO is a | + | 1OLO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1OLO OCA]. |
==Reference== | ==Reference== | ||
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[[Category: transcription]] | [[Category: transcription]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 13:08:24 2007'' |
Revision as of 11:03, 5 November 2007
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HEXAMERIC REPLICATIVE DNA HELICASE REPA FROM PLASMID RSF1010- CUBIC CRYSTAL STRUCTURE
Overview
In the known monoclinic crystals the 3-dimensional structure of the, hexameric, replicative helicase RepA encoded by plasmid RSF1010 shows, 6-fold rotational symmetry. In contrast, in the cubic crystal form at 2.55, A resolution described here RepA has 3-fold symmetry and consists of a, trimer of dimers. To study structure-function relationships, a series of, repA deletion mutants and mutations yielding single amino acid exchanges, were constructed and the respective gene products were analyzed in vivo, and in vitro. Hexamerization of RepA occurs via the N-terminus and is, required for NTP hydrolysis. The C-terminus is essential both for the, interaction with the replication machinery and for the helicase activity., Functional analyses of RepA variants with single amino acid exchanges, confirmed most of the predictions that were based on the published, 3-dimensional structure. Of the five motifs conserved in family 4, helicases, all residues conserved in RepA and T7 gp4 helicases participate, in DNA unwinding. Residues K42, E76, D77, D139 and H178, proposed to play, key roles in catalyzing the hydrolysis of NTPs, are essential for RepA, activity. Residue H178 of motif H3 couples nucleotide consumption to DNA, strand separation.
About this Structure
1OLO is a Single protein structure of sequence from Escherichia coli with SO4 as ligand. Structure known Active Site: AC1. Full crystallographic information is available from OCA.
Reference
Hexameric RSF1010 helicase RepA: the structural and functional importance of single amino acid residues., Ziegelin G, Niedenzu T, Lurz R, Saenger W, Lanka E, Nucleic Acids Res. 2003 Oct 15;31(20):5917-29. PMID:14530440
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