3fld

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Crystal structure of the trai c-terminal domainCrystal structure of the trai c-terminal domain

Structural highlights

3fld is a 2 chain structure with sequence from Ecoli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Gene:ECOK12F104, traI (ECOLI)
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[TRAI1_ECOLI] Conjugative DNA transfer (CDT) is the unidirectional transfer of ssDNA plasmid from a donor to a recipient cell. It is the central mechanism by which antibiotic resistance and virulence factors are propagated in bacterial populations. Part of the relaxosome, which facilitates a site- and strand-specific cut in the origin of transfer by TraI, at the nic site. Relaxosome formation requires binding of IHF and TraY to the oriT region, which then faciliates binding of TraI relaxase. TraI forms a covalent 5'-phosphotyrosine intermediate linkage to the ssDNA. The transesterified T-strand moves from the donor cell to the recipient cell in a 5'to 3' direction, with the DNA helicase activity of TraI unwinding the DNA. DNA transfer occurs via the conjugative pore (transferosome) an intercellular junction mediated by a type IV secretion system, with TraD providing the means to link the relaxosome to the conjugative pore. The relaxase completes DNA transfer by reversing the covalent phosphotyrosine linkage and releasing the T-strand.[1] [2] [3] [4] [5] TraI has also been identified as DNA helicase I. DNA. helicase I is a potent, highly processive DNA-dependent ATPase, able to unwind about 1.1 kb dsDNA per second in a 5' to 3' manner.[6] [7] [8] [9] [10]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

TraI relaxase-helicase is the central catalytic component of the multiprotein relaxosome complex responsible for conjugative DNA transfer (CDT) between bacterial cells. CDT is a primary mechanism for the lateral propagation of microbial genetic material, including the spread of antibiotic resistance genes. The 2.4-A resolution crystal structure of the C-terminal domain of the multifunctional Escherichia coli F (fertility) plasmid TraI protein is presented, and specific structural regions essential for CDT are identified. The crystal structure reveals a novel fold composed of a 28-residue N-terminal alpha-domain connected by a proline-rich loop to a compact alpha/beta-domain. Both the globular nature of the alpha/beta-domain and the presence as well as rigidity of the proline-rich loop are required for DNA transfer and single-stranded DNA binding. Taken together, these data establish the specific structural features of this noncatalytic domain that are essential to DNA conjugation.

A Novel Fold in the TraI Relaxase-Helicase C-Terminal Domain Is Essential for Conjugative DNA Transfer.,Guogas LM, Kennedy SA, Lee JH, Redinbo MR J Mol Biol. 2009 Feb 20;386(2):554-68. Epub 2008 Dec 30. PMID:19136009[11]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Street LM, Harley MJ, Stern JC, Larkin C, Williams SL, Miller DL, Dohm JA, Rodgers ME, Schildbach JF. Subdomain organization and catalytic residues of the F factor TraI relaxase domain. Biochim Biophys Acta. 2003 Mar 21;1646(1-2):86-99. PMID:12637015
  2. Abdel-Monem M, Taucher-Scholz G, Klinkert MQ. Identification of Escherichia coli DNA helicase I as the traI gene product of the F sex factor. Proc Natl Acad Sci U S A. 1983 Aug;80(15):4659-63. PMID:6308637
  3. Matson SW, Nelson WC, Morton BS. Characterization of the reaction product of the oriT nicking reaction catalyzed by Escherichia coli DNA helicase I. J Bacteriol. 1993 May;175(9):2599-606. PMID:8386720
  4. Nelson WC, Howard MT, Sherman JA, Matson SW. The traY gene product and integration host factor stimulate Escherichia coli DNA helicase I-catalyzed nicking at the F plasmid oriT. J Biol Chem. 1995 Nov 24;270(47):28374-80. PMID:7499339
  5. Stern JC, Schildbach JF. DNA recognition by F factor TraI36: highly sequence-specific binding of single-stranded DNA. Biochemistry. 2001 Sep 25;40(38):11586-95. PMID:11560509
  6. Street LM, Harley MJ, Stern JC, Larkin C, Williams SL, Miller DL, Dohm JA, Rodgers ME, Schildbach JF. Subdomain organization and catalytic residues of the F factor TraI relaxase domain. Biochim Biophys Acta. 2003 Mar 21;1646(1-2):86-99. PMID:12637015
  7. Abdel-Monem M, Taucher-Scholz G, Klinkert MQ. Identification of Escherichia coli DNA helicase I as the traI gene product of the F sex factor. Proc Natl Acad Sci U S A. 1983 Aug;80(15):4659-63. PMID:6308637
  8. Matson SW, Nelson WC, Morton BS. Characterization of the reaction product of the oriT nicking reaction catalyzed by Escherichia coli DNA helicase I. J Bacteriol. 1993 May;175(9):2599-606. PMID:8386720
  9. Nelson WC, Howard MT, Sherman JA, Matson SW. The traY gene product and integration host factor stimulate Escherichia coli DNA helicase I-catalyzed nicking at the F plasmid oriT. J Biol Chem. 1995 Nov 24;270(47):28374-80. PMID:7499339
  10. Stern JC, Schildbach JF. DNA recognition by F factor TraI36: highly sequence-specific binding of single-stranded DNA. Biochemistry. 2001 Sep 25;40(38):11586-95. PMID:11560509
  11. Guogas LM, Kennedy SA, Lee JH, Redinbo MR. A Novel Fold in the TraI Relaxase-Helicase C-Terminal Domain Is Essential for Conjugative DNA Transfer. J Mol Biol. 2009 Feb 20;386(2):554-68. Epub 2008 Dec 30. PMID:19136009 doi:S0022-2836(08)01579-9

3fld, resolution 2.40Å

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