Thermally stable harpin, HrpZPss is sensitive to chemical denaturants: Probing tryptophan environment, chemical and thermal unfolding by fluorescence spectroscopy

Tarafdar, Pradip K.; Vedantam, Lakshmi Vasudev; Podile, Appa Rao; Swamy, Musti J.

doi:10.1016/j.biochi.2013.09.006

Cited by 4 publications

(4 citation statements)

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“…A quencher is often highly selective for a particular fluorophore due to the quenching mechanism, thus much structural information can be obtained about an individual molecule in a macromolecular environment. For example fluorescence quenching of tryptophan in proteins is used to explore their intrinsic and extrinsic structure, and even their conformation,18–21 and the apparent diffusion coefficient of oxygen in membranes can be determined by quenching probes bound to lipid bilayers by using oxygen as a quencher 22. 23 Based on a frequent observation, if two π‐conjugated aromatic systems are in a direct connection through HB bonding the fluorescence quenching of either the donor or acceptor molecule occurs.…”

Section: Introductionmentioning

confidence: 99%

Solvatochromic Study of Highly Fluorescent Alkylated Isocyanonaphthalenes, Their π‐Stacking, Hydrogen‐Bonding Complexation, and Quenching with Pyridine

et al. 2014

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Mono- and dialkylated derivatives of 1-amino-5-isocyanonaphthalene (ICAN) were studied as new members of a multifunctional, easy-to-prepare fluorophore family, which showed excellent solvatochromic properties. The monoallyl derivative and the starting ICAN exhibited strong fluorescence quenching in the presence of small amounts of pyridine. The formation of a hydrogen-bonded ground-state pyridine complex was detected; however, analysis of quantum chemical calculations suggested the presence of an additional π-stacked pyridine complex. The Stern-Volmer plot of the quenching process exhibited a downward curvature and after reaching a minimum the fluorescence intensity increased back to a significant level at high pyridine concentrations. Significant fluorescence was observed even in pure pyridine. A new mechanism and a simple mathematical equation were derived to explain the downward curvature and the remaining fluorescence by the formation of a fluorescent π-stacked complex.

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Section: Introductionmentioning

confidence: 99%

Solvatochromic Study of Highly Fluorescent Alkylated Isocyanonaphthalenes, Their π‐Stacking, Hydrogen‐Bonding Complexation, and Quenching with Pyridine

et al. 2014

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“…Therefore, the ΔC p for this transition couldn't be estimated from the DSC studies; nonetheless, we assume that the structure of the denatured monomer of HrpZ Pss is very close to the structure of the intermediate after transition 2. Indeed, recent fluorescence studies show that the emission λ max of HrpZ Pss , observed around 328 nm at room temperature, increases to 347.5 nm at 76°C, suggesting that the tryptophan environment is very close to the aqueous environment at this temperature [20] .…”

Section: Resultsmentioning

confidence: 96%

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

et al. 2014

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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.

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“…Harpins are elicitors with approximately 10–60 kDa, encoded by sequences located in the hypersensitive response and pathogenicity ( hrp ) gene cluster and released through the type III secretion system [ 16 , 20 ]. Most harpins are acidic, hydrophilic, and thermostable and are sensitive to chemically denaturing proteins because of their distinctive sequences and architectures [ 16 , 19 , 20 , 21 , 22 ]. Harpins are enriched with glycine and serine but carry few aromatic amino acids and low levels of cysteine, which is an amino acid that contributes to disulfide bonds.…”

Section: Harpinsmentioning

confidence: 99%

Characteristics, Roles and Applications of Proteinaceous Elicitors from Pathogens in Plant Immunity

Liu²,

Ma³

et al. 2023

Life

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In interactions between pathogens and plants, pathogens secrete many molecules that facilitate plant infection, and some of these compounds are recognized by plant pattern recognition receptors (PRRs), which induce immune responses. Molecules in both pathogens and plants that trigger immune responses in plants are termed elicitors. On the basis of their chemical content, elicitors can be classified into carbohydrates, lipopeptides, proteinaceous compounds and other types. Although many studies have focused on the involvement of elicitors in plants, especially on pathophysiological changes induced by elicitors in plants and the mechanisms mediating these changes, there is a lack of up-to-date reviews on the characteristics and functions of proteinaceous elicitors. In this mini-review, we provide an overview of the up-to-date knowledge on several important families of pathogenic proteinaceous elicitors (i.e., harpins, necrosis- and ethylene-inducing peptide 1 (nep1)-like proteins (NLPs) and elicitins), focusing mainly on their structures, characteristics and effects on plants, specifically on their roles in plant immune responses. A solid understanding of elicitors may be helpful to decrease the use of agrochemicals in agriculture and gardening, generate more resistant germplasms and increase crop yields.

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Thermally stable harpin, HrpZPss is sensitive to chemical denaturants: Probing tryptophan environment, chemical and thermal unfolding by fluorescence spectroscopy

Cited by 4 publications

References 32 publications

Solvatochromic Study of Highly Fluorescent Alkylated Isocyanonaphthalenes, Their π‐Stacking, Hydrogen‐Bonding Complexation, and Quenching with Pyridine

Solvatochromic Study of Highly Fluorescent Alkylated Isocyanonaphthalenes, Their π‐Stacking, Hydrogen‐Bonding Complexation, and Quenching with Pyridine

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

Characteristics, Roles and Applications of Proteinaceous Elicitors from Pathogens in Plant Immunity

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