Ehrlichia chaffeensis TRP120 nucleomodulin binds DNA with disordered tandem repeat domain

Valerie J. Klema, Krishna Mohan Sepuru, Nadia Füllbrunn, Tierra R. Farris, Paige S. Dunphy, Jere McBride, Krishna Rajarathnam, Kyung Choi

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Ehrlichia chaffeensis, the causative agent of human monocytotropic ehrlichiosis, secretes several effector proteins that bind host DNA to modulate host gene expression. The tandem repeat protein 120 (TRP120), one of the largest effector proteins, has four nearly identical tandem repeat (TR) regions that each consists of 80 amino acids. In addition to playing a role in ehrlichial binding and internalization, TRP120 translocates to the host nucleus where it is thought to function as a transcription factor that modulates gene expression. However, sequence analysis of TRP120 does not identify the presence of DNA-binding or trans-activation domains typical of classical eukaryotic transcription factors. Thus, the mechanism by which TRP120 binds DNA and modulates gene expression remains elusive. Herein, we expressed the TR regions of the TRP120 protein, and characterized its solution structure and ability to bind DNA. TRP120, expressed as either a one or two TR repeat, is a monomer in solution, and is mostly disordered as determined by circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy. Using NMR spectroscopy, we further show that the 1 TR construct selectively binds GC-rich DNA. Although low pH was required for TRP120 TR-DNA interaction, acidic pH alone does not induce any significant structural changes in the TR region. This suggests that TRP120 folds into an ordered structure upon forming a protein-DNA complex, and thus folding of TRP120 TR is coupled with DNA binding.

Original languageEnglish (US)
Article numbere0194891
JournalPLoS One
Volume13
Issue number4
DOIs
StatePublished - Apr 1 2018

Fingerprint

Ehrlichia chaffeensis
Tandem Repeat Sequences
tandem repeat sequences
DNA
Proteins
proteins
Gene expression
Gene Expression
gene expression
Nuclear magnetic resonance spectroscopy
nuclear magnetic resonance spectroscopy
Transcription Factors
Magnetic Resonance Spectroscopy
transcription factors
Ehrlichiosis
circular dichroism spectroscopy
ehrlichiosis

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

Ehrlichia chaffeensis TRP120 nucleomodulin binds DNA with disordered tandem repeat domain. / Klema, Valerie J.; Sepuru, Krishna Mohan; Füllbrunn, Nadia; Farris, Tierra R.; Dunphy, Paige S.; McBride, Jere; Rajarathnam, Krishna; Choi, Kyung.

In: PLoS One, Vol. 13, No. 4, e0194891, 01.04.2018.

Research output: Contribution to journalArticle

Klema, Valerie J. ; Sepuru, Krishna Mohan ; Füllbrunn, Nadia ; Farris, Tierra R. ; Dunphy, Paige S. ; McBride, Jere ; Rajarathnam, Krishna ; Choi, Kyung. / Ehrlichia chaffeensis TRP120 nucleomodulin binds DNA with disordered tandem repeat domain. In: PLoS One. 2018 ; Vol. 13, No. 4.
@article{8708e21fa8a445988b0352bb6b65e413,
title = "Ehrlichia chaffeensis TRP120 nucleomodulin binds DNA with disordered tandem repeat domain",
abstract = "Ehrlichia chaffeensis, the causative agent of human monocytotropic ehrlichiosis, secretes several effector proteins that bind host DNA to modulate host gene expression. The tandem repeat protein 120 (TRP120), one of the largest effector proteins, has four nearly identical tandem repeat (TR) regions that each consists of 80 amino acids. In addition to playing a role in ehrlichial binding and internalization, TRP120 translocates to the host nucleus where it is thought to function as a transcription factor that modulates gene expression. However, sequence analysis of TRP120 does not identify the presence of DNA-binding or trans-activation domains typical of classical eukaryotic transcription factors. Thus, the mechanism by which TRP120 binds DNA and modulates gene expression remains elusive. Herein, we expressed the TR regions of the TRP120 protein, and characterized its solution structure and ability to bind DNA. TRP120, expressed as either a one or two TR repeat, is a monomer in solution, and is mostly disordered as determined by circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy. Using NMR spectroscopy, we further show that the 1 TR construct selectively binds GC-rich DNA. Although low pH was required for TRP120 TR-DNA interaction, acidic pH alone does not induce any significant structural changes in the TR region. This suggests that TRP120 folds into an ordered structure upon forming a protein-DNA complex, and thus folding of TRP120 TR is coupled with DNA binding.",
author = "Klema, {Valerie J.} and Sepuru, {Krishna Mohan} and Nadia F{\"u}llbrunn and Farris, {Tierra R.} and Dunphy, {Paige S.} and Jere McBride and Krishna Rajarathnam and Kyung Choi",
year = "2018",
month = "4",
day = "1",
doi = "10.1371/journal.pone.0194891",
language = "English (US)",
volume = "13",
journal = "PLoS One",
issn = "1932-6203",
publisher = "Public Library of Science",
number = "4",

}

TY - JOUR

T1 - Ehrlichia chaffeensis TRP120 nucleomodulin binds DNA with disordered tandem repeat domain

AU - Klema, Valerie J.

AU - Sepuru, Krishna Mohan

AU - Füllbrunn, Nadia

AU - Farris, Tierra R.

AU - Dunphy, Paige S.

AU - McBride, Jere

AU - Rajarathnam, Krishna

AU - Choi, Kyung

PY - 2018/4/1

Y1 - 2018/4/1

N2 - Ehrlichia chaffeensis, the causative agent of human monocytotropic ehrlichiosis, secretes several effector proteins that bind host DNA to modulate host gene expression. The tandem repeat protein 120 (TRP120), one of the largest effector proteins, has four nearly identical tandem repeat (TR) regions that each consists of 80 amino acids. In addition to playing a role in ehrlichial binding and internalization, TRP120 translocates to the host nucleus where it is thought to function as a transcription factor that modulates gene expression. However, sequence analysis of TRP120 does not identify the presence of DNA-binding or trans-activation domains typical of classical eukaryotic transcription factors. Thus, the mechanism by which TRP120 binds DNA and modulates gene expression remains elusive. Herein, we expressed the TR regions of the TRP120 protein, and characterized its solution structure and ability to bind DNA. TRP120, expressed as either a one or two TR repeat, is a monomer in solution, and is mostly disordered as determined by circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy. Using NMR spectroscopy, we further show that the 1 TR construct selectively binds GC-rich DNA. Although low pH was required for TRP120 TR-DNA interaction, acidic pH alone does not induce any significant structural changes in the TR region. This suggests that TRP120 folds into an ordered structure upon forming a protein-DNA complex, and thus folding of TRP120 TR is coupled with DNA binding.

AB - Ehrlichia chaffeensis, the causative agent of human monocytotropic ehrlichiosis, secretes several effector proteins that bind host DNA to modulate host gene expression. The tandem repeat protein 120 (TRP120), one of the largest effector proteins, has four nearly identical tandem repeat (TR) regions that each consists of 80 amino acids. In addition to playing a role in ehrlichial binding and internalization, TRP120 translocates to the host nucleus where it is thought to function as a transcription factor that modulates gene expression. However, sequence analysis of TRP120 does not identify the presence of DNA-binding or trans-activation domains typical of classical eukaryotic transcription factors. Thus, the mechanism by which TRP120 binds DNA and modulates gene expression remains elusive. Herein, we expressed the TR regions of the TRP120 protein, and characterized its solution structure and ability to bind DNA. TRP120, expressed as either a one or two TR repeat, is a monomer in solution, and is mostly disordered as determined by circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy. Using NMR spectroscopy, we further show that the 1 TR construct selectively binds GC-rich DNA. Although low pH was required for TRP120 TR-DNA interaction, acidic pH alone does not induce any significant structural changes in the TR region. This suggests that TRP120 folds into an ordered structure upon forming a protein-DNA complex, and thus folding of TRP120 TR is coupled with DNA binding.

UR - http://www.scopus.com/inward/record.url?scp=85045201970&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85045201970&partnerID=8YFLogxK

U2 - 10.1371/journal.pone.0194891

DO - 10.1371/journal.pone.0194891

M3 - Article

VL - 13

JO - PLoS One

JF - PLoS One

SN - 1932-6203

IS - 4

M1 - e0194891

ER -