Oligomerization, Conformational Stability and Thermal Unfolding of Harpin, HrpZPss and Its Hypersensitive Response-Inducing C-Terminal Fragment, C-214-HrpZPss.

Authors

Pradip K Tarafdar, School of Chemistry, University of Hyderabad; Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics
Lakshmi Vasudev Vedantam, Department of Plant Sciences, School of Life Sciences, University of Hyderabad; Shanta Biotechnics Ltd
Rajeshwer S Sankhala, School of Chemistry, University of Hyderabad; Department of Biochemistry and Molecular Biology, Thomas Jefferson UniversityFollow
Pallinti Purushotham, Department of Plant Sciences, School of Life Sciences, University of Hyderabad
Appa Rao Podile, Department of Plant Sciences, School of Life Sciences, University of Hyderabad
Musti J Swamy, School of Chemistry, University of Hyderabad

Document Type

Abstract

Publication Date

12-12-2014

Comments

This article has been peer reviewed. It was published in: PLoS ONE.

Volume 9, Issue 12, 12 December 2014, Article number e109871.

The published version is available at DOI: 10.1371/journal.pone.0109871

Copyright © 2014 Tarafdar et al.

Abstract

HrpZ-a harpin from Pseudomonas syringae-is a highly thermostable protein that exhibits multifunctional abilities e.g., it elicits hypersensitive response (HR), enhances plant growth, acts as a virulence factor, and forms pores in plant plasma membranes as well as artificial membranes. However, the molecular mechanism of its biological activity and high thermal stability remained poorly understood. HR inducing abilities of non-overlapping short deletion mutants of harpins put further constraints on the ability to establish structure-activity relationships. We characterized HrpZPss from Pseudomonas syringae pv. syringae and its HR inducing C-terminal fragment with 214 amino acids (C-214-HrpZPss) using calorimetric, spectroscopic and microscopic approaches. Both C-214-HrpZPss and HrpZPss were found to form oligomers. We propose that leucine-zipper-like motifs may take part in the formation of oligomeric aggregates, and oligomerization could be related to HR elicitation. CD, DSC and fluorescence studies showed that the thermal unfolding of these proteins is complex and involves multiple steps. The comparable conformational stability at 25°C (∼10.0 kcal/mol) of HrpZPss and C-214-HrpZPss further suggest that their structures are flexible, and the flexibility allows them to adopt proper conformation for multifunctional abilities.

Recommended Citation

Tarafdar, Pradip K; Vedantam, Lakshmi Vasudev; Sankhala, Rajeshwer S; Purushotham, Pallinti; Podile, Appa Rao; and Swamy, Musti J, "Oligomerization, Conformational Stability and Thermal Unfolding of Harpin, HrpZPss and Its Hypersensitive Response-Inducing C-Terminal Fragment, C-214-HrpZPss." (2014). Department of Biochemistry and Molecular Biology Faculty Papers. Paper 84.
https://jdc.jefferson.edu/bmpfp/84

PubMed ID

25502017