Cryo-EM structure of a relaxase reveals the molecular basis of DNA unwinding during bacterial conjugation

Aravindan Ilangovan; Christopher W. M. Kay; Sandro Roier; Hassane El Mkami; Enrico Salvadori; Ellen L. Zechner; Giulia Zanetti; Gabriel Waksman

doi:10.1016/j.cell.2017.04.010

Cryo-EM structure of a relaxase reveals the molecular basis of DNA unwinding during bacterial conjugation

Aravindan Ilangovan, Christopher W. M. Kay, Sandro Roier, Hassane El Mkami, Enrico Salvadori, Ellen L. Zechner, Giulia Zanetti, Gabriel Waksman

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

Abstract

Relaxases play essential roles in conjugation, the main process by which bacteria exchange genetic material, notably antibiotic resistance genes. They are bifunctional enzymes containing a trans-esterase activity, which is responsible for nicking the DNA strand to be transferred and for covalent attachment to the resulting 5′-phosphate end, and a helicase activity, which is responsible for unwinding the DNA while it is being transported to a recipient cell. Here we show that these two activities are carried out by two conformers that can both load simultaneously on the origin of transfer DNA. We solve the structure of one of these conformers by cryo electron microscopy to near-atomic resolution, elucidating the molecular basis of helicase function by relaxases and revealing insights into the mechanistic events taking place in the cell prior to substrate transport during conjugation.

Original language	English
Article number	e12
Pages (from-to)	708-721
Number of pages	27
Journal	Cell
Volume	169
Issue number	4
Early online date	27 Apr 2017
DOIs	https://doi.org/10.1016/j.cell.2017.04.010
Publication status	Published - 4 May 2017

Keywords

Relaxase
TraI
Bacterial conjugation
Cryo-electron microscopy
Type IV secretion system
Structural biology

Access to Document

10.1016/j.cell.2017.04.010Licence: CC BY

ElMkami_2017_Cell_Cryo-EMStructure_CC
© 2017 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Final published version, 9.11 MBLicence: CC BY

Cite this

@article{3fc54b3c5f5e49c992b17b444ffe60ec,

title = "Cryo-EM structure of a relaxase reveals the molecular basis of DNA unwinding during bacterial conjugation",

abstract = "Relaxases play essential roles in conjugation, the main process by which bacteria exchange genetic material, notably antibiotic resistance genes. They are bifunctional enzymes containing a trans-esterase activity, which is responsible for nicking the DNA strand to be transferred and for covalent attachment to the resulting 5′-phosphate end, and a helicase activity, which is responsible for unwinding the DNA while it is being transported to a recipient cell. Here we show that these two activities are carried out by two conformers that can both load simultaneously on the origin of transfer DNA. We solve the structure of one of these conformers by cryo electron microscopy to near-atomic resolution, elucidating the molecular basis of helicase function by relaxases and revealing insights into the mechanistic events taking place in the cell prior to substrate transport during conjugation.",

keywords = "Relaxase, TraI, Bacterial conjugation, Cryo-electron microscopy, Type IV secretion system, Structural biology",

author = "Aravindan Ilangovan and Kay, {Christopher W. M.} and Sandro Roier and {El Mkami}, Hassane and Enrico Salvadori and Zechner, {Ellen L.} and Giulia Zanetti and Gabriel Waksman",

note = "This work was supported by Wellcome Trust grant 098302 to G.W., a Royal Society Dorothy Hodgkin fellowship to G.Z. DH130048, and Austrian Science Fund (FWF) grants P24016 and W901 DK Molecular Enzymology to E.L.Z. S.R. is a BioTechMed-Graz PostDoc. H.E.M. and the EPR Facility at St Andrews are supported in part by Wellcome Trust grant 099149/Z/12/Z.",

year = "2017",

month = may,

day = "4",

doi = "10.1016/j.cell.2017.04.010",

language = "English",

volume = "169",

pages = "708--721",

journal = "Cell",

issn = "0092-8674",

publisher = "Cell Press",

number = "4",

}

TY - JOUR

T1 - Cryo-EM structure of a relaxase reveals the molecular basis of DNA unwinding during bacterial conjugation

AU - Ilangovan, Aravindan

AU - Kay, Christopher W. M.

AU - Roier, Sandro

AU - El Mkami, Hassane

AU - Salvadori, Enrico

AU - Zechner, Ellen L.

AU - Zanetti, Giulia

AU - Waksman, Gabriel

N1 - This work was supported by Wellcome Trust grant 098302 to G.W., a Royal Society Dorothy Hodgkin fellowship to G.Z. DH130048, and Austrian Science Fund (FWF) grants P24016 and W901 DK Molecular Enzymology to E.L.Z. S.R. is a BioTechMed-Graz PostDoc. H.E.M. and the EPR Facility at St Andrews are supported in part by Wellcome Trust grant 099149/Z/12/Z.

PY - 2017/5/4

Y1 - 2017/5/4

N2 - Relaxases play essential roles in conjugation, the main process by which bacteria exchange genetic material, notably antibiotic resistance genes. They are bifunctional enzymes containing a trans-esterase activity, which is responsible for nicking the DNA strand to be transferred and for covalent attachment to the resulting 5′-phosphate end, and a helicase activity, which is responsible for unwinding the DNA while it is being transported to a recipient cell. Here we show that these two activities are carried out by two conformers that can both load simultaneously on the origin of transfer DNA. We solve the structure of one of these conformers by cryo electron microscopy to near-atomic resolution, elucidating the molecular basis of helicase function by relaxases and revealing insights into the mechanistic events taking place in the cell prior to substrate transport during conjugation.

AB - Relaxases play essential roles in conjugation, the main process by which bacteria exchange genetic material, notably antibiotic resistance genes. They are bifunctional enzymes containing a trans-esterase activity, which is responsible for nicking the DNA strand to be transferred and for covalent attachment to the resulting 5′-phosphate end, and a helicase activity, which is responsible for unwinding the DNA while it is being transported to a recipient cell. Here we show that these two activities are carried out by two conformers that can both load simultaneously on the origin of transfer DNA. We solve the structure of one of these conformers by cryo electron microscopy to near-atomic resolution, elucidating the molecular basis of helicase function by relaxases and revealing insights into the mechanistic events taking place in the cell prior to substrate transport during conjugation.

KW - Relaxase

KW - TraI

KW - Bacterial conjugation

KW - Cryo-electron microscopy

KW - Type IV secretion system

KW - Structural biology

UR - http://www.sciencedirect.com/science/article/pii/S0092867417304233#appd002

U2 - 10.1016/j.cell.2017.04.010

DO - 10.1016/j.cell.2017.04.010

M3 - Article

SN - 0092-8674

VL - 169

SP - 708

EP - 721

JO - Cell

JF - Cell

IS - 4

M1 - e12

ER -

Cryo-EM structure of a relaxase reveals the molecular basis of DNA unwinding during bacterial conjugation

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

State of the art pulse EPR instrumentati: State of the art pulse EPR instrumentation for long range distance measurements in biomacromolecules

Cite this

Cryo-EM structure of a relaxase reveals the molecular basis of DNA unwinding during bacterial conjugation

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Projects

State of the art pulse EPR instrumentati: State of the art pulse EPR instrumentation for long range distance measurements in biomacromolecules

Cite this