StrainAgrobacterium tumefaciens plasmid Ti (NC_002377)
Repliconplasmid Ti [Browse all T4SS(s) in this replicon]
Functioneffector translocation and conjugation
ClassificationType IVA; Type P
experimental Experimental investigation has been performed on this T4SS.

T4SS components

The information of T4SS components from NC_002377
#Locus tag (Gene)Coordinates [+/-], size (bp)Protein GIProductComponent
1pTi_126 (virJ)148762..149529 [+], 76810955142hypothetical protein 
2pTi_127 (virB1)151232..151951 [+], 72010955143type IV secretion system lytic transglycosylase VirB1  VirB1
3pTi_128 (virB2)151966..152331 [+], 36610955144type IV secretion system pilin subunit VirB2  VirB2
4pTi_129 (virB3)152331..152657 [+], 32710955145type IV secretion system protein VirB3  VirB3
5pTi_130 (virB4)152657..155026 [+], 237010955146type IV secretion system protein VirB4  VirB4
6pTi_131 (virB5)155041..155703 [+], 66310955147type IV secretion system protein VirB5  VirB5
7pTi_132 (virB6)155800..156687 [+], 88810955148type IV secretion system protein VirB6  VirB6
8pTi_133 (virB7)156721..156888 [+], 16810955149type IV secretion system lipoprotein VirB7  VirB7
9pTi_134 (virB8)156896..157588 [+], 69310955150type IV secretion system protein VirB8  VirB8
10pTi_135 (virB9)157585..158466 [+], 88210955151type IV secretion system protein VirB9  VirB9
11pTi_136 (virB10)158463..159596 [+], 113410955152type IV secretion system protein VirB10  VirB10
12pTi_137 (virB11)159636..160667 [+], 103210955153type IV secretion system protein VirB11  VirB11
13pTi_138 (virG)160877..161602 [+], 72610955154two-component response regulator VirG 
14pTi_139 (virC2)166669..167277 [-], 60910955155putative crown gall tumor protein VirC2 
15pTi_140 (virC1)167280..167975 [-], 69610955156putative crown gall tumor protein VirC1  accesspry protein
16pTi_141 (virD1)168244..168687 [+], 44410955157type IV secretion system T-DNA border endonuclease VirD1 
17pTi_142 (virD2)168721..169995 [+], 127510955158type IV secretion system T-DNA border endonuclease VirD2 
18pTi_143 (virD3)170015..170620 [+], 60610955159hypothetical protein 
19pTi_144 (virD4)170649..172619 [+], 197110955160type IV secretion system protein VirD4  VirD4
20pTi_145 (virD5)172711..175212 [+], 250210955161hypothetical protein 
21pTi_146 (virE1)175665..175862 [+], 19810955162type IV secretion system chaperone VirE1  accesspry protein
22pTi_147 (virE2)175867..177468 [+], 160210955163type IV secretion system single-stranded DNA binding protein VirE2 
accesspry protein This T4SS contains information of accessory protein.
flank Genes in the 5-Kb flanking regions if available, or non-essential genes in the T4SS gene cluster if any.

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Proteins        Genes
This system delivers both DNA and proteins into plant cell. The transferred DNA (T-DNA) region: NC_002377: 1..22878)

VirD2, VirD5, VirE2, VirE3, VirF

The information of protein effectors
#Locus tag (Gene)Coordinates [+/-], size (bp)Protein GIProduct  *
1pTi_142 (virD2)168721..169995 [+], 127510955158type IV secretion system T-DNA border endonuclease VirD2experimental  VirD2
2pTi_145 (virD5)172711..175212 [+], 250210955161hypothetical proteinexperimental  VirD5
3pTi_147 (virE2)175867..177468 [+], 160210955163type IV secretion system single-stranded DNA binding protein VirE2experimental  VirE2
4pTi_148 (virE3)177534..179552 [+], 201910955164hypothetical proteinexperimental  VirE3
5pTi_152 (virF)184764..185372 [+], 60910955168hypothetical proteinexperimental  VirF
experimental T4SE derived from experimental literature.

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Proteins        Genes
The information on requirements for T4SS substrate-channel docking

Certain T4SS substrates require secretion chaperones for translocation. These chaperones often possess physical properties (small size of 15 kDa, acidic pI, and amphipathic helices) resembling those of chaperones associated with the type III secretion systems, a family of macromolecular translocation systems ancestrally related to bacterial flagella.

#Accessory protein(GI)motif(s)Substrate(s)FunctionReference
1VirC1 (10955156)NDVirD2VirC1 pairwise interacts with the processing factors VirD2 relaxase, VirC2, and VirD1 to stimulate generation of multiple copies per cell of the T-DNA substrate. VirC1 promotes conjugative T-DNA transfer.(1) PubMed: 17505518
2VirE1 chaperone (10955162)CT50aa sufficient (interacts with the VirD4 T4CP. CT100aa(VirE2) sufficient for the T4CP interation)VirE2Translocation of the VirE2 effector through the A. tumefaciens VirB/VirD4 T4SS requires VirE1.(2) PubMed: 19946141
1.Substrate(s): For the conjugation systems, the listed proteins are relaxases that bind a cognate T4CP and are delivered to recipient cells. For the effector translocator systems, the listed proteins are effectors that play a role in the infection processes of the bacterial pathogen.
2.motif(s):The motifs listed are required for substrate translocation. In some cases, the protein or its C-terminal fragment (CT) is sufficient to mediate translocation to target cells, as shown by fusion to a reporter protein such as Cre recombinase or adenylate cyclase. Amino acids (aa) at positions listed relative to the C-terminal fragment (subscript) are required for translocation, as shown by mutational analysis. ND, not determined. Parentheses indicate that the interaction between a protein substrate and a cognate T4CP has been experimentally shown.
3.Accessory protein: Accessory factors required for T4SS channel docking or translocation. The proposed function in mediating substrate-T4SS channel docking is shown in parentheses.PubMed:19946141

(1) Atmakuri K; Cascales E; Burton OT; Banta LM; Christie PJ (2007). Agrobacterium ParA/MinD-like VirC1 spatially coordinates early conjugative DNA transfer reactions. EMBO J. 26(10):2540-51. [PudMed:17505518] experimental
(2) Alvarez-Martinez CE; Christie PJ (2009). Biological diversity of prokaryotic type IV secretion systems. Microbiol Mol Biol Rev. 73(4):775-808. [PudMed:19946141]
(1) Ream W (2009). Agrobacterium tumefaciens and A. rhizogenes use different proteins to transport bacterial DNA into the plant cell nucleus. Microb Biotechnol. 2(4):416-27. [PudMed:21255274]