Dimerization of Plant Defensin NaD1 Enhances Its Antifungal Activity

Lay, Fung T.; Mills, Grant; Poon, Ivan K. H.; Cowieson, Nathan; Kirby, Nigel; Baxter, Amy A.; Weerden, Nicole L. van der; Dogovski, Con; Perugini, Matthew A.; Anderson, Marilyn A.; Kvansakul, Marc; Hulett, Mark D.

doi:10.1074/jbc.m111.331009

Cited by 69 publications

(92 citation statements)

References 88 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…More recently, we demonstrated that dimerization of NaD1 is important for antifungal activity. The dimer has an extensive positively charged surface that may promote the interaction with negatively charged moieties within the fungal cell wall and/or membrane (15). As the ability of defensins to form dimers has been reported previously (17), these data suggest that dimeric configurations of defensins are likely to be of functional importance for their antimicrobial activity.…”

supporting

confidence: 62%

“…TPP3 and related defensins in the presence or absence of PIP2 were cross-linked with bis(sulfosuccinimidyl)suberate (BS 3 ) and analyzed by reducing SDS-PAGE as described previously (15). Transmission electron microscopy (TEM).…”

Section: Methodsmentioning

confidence: 99%

“…The identification and characterization of class II defensins, found mainly in floral tissue and in seeds, have been limited. NaD1, a solanaceous defensin from the flowers of the ornamental tobacco (Nicotiana alata), exhibits fungicidal and growth-inhibitory activities toward several plant-pathogenic fungi, including Fusarium oxysporum, Fusarium graminearum, Botrytis cinerea, Saccharomyces cerevisiae, Candida albicans, and several Aspergillus and Cryptococcus species (6,(12)(13)(14)(15). NaD1 has a three-stage mechanism that involves cell wall binding, membrane permeabilization, and entry into the cytoplasm that results in cell death for both hyphal and yeast fungal forms (14).…”

mentioning

confidence: 99%

See 2 more Smart Citations

The Tomato Defensin TPP3 Binds Phosphatidylinositol (4,5)-Bisphosphate via a Conserved Dimeric Cationic Grip Conformation To Mediate Cell Lysis

Baxter

Richter

Lay

et al. 2015

Molecular and Cellular Biology

Self Cite

104

View full text Add to dashboard Cite

Defensins are a class of ubiquitously expressed cationic antimicrobial peptides (CAPs) that play an important role in innate defense. Plant defensins are active against a broad range of microbial pathogens and act via multiple mechanisms, including cell membrane permeabilization. The cytolytic activity of defensins has been proposed to involve interaction with specific lipid components in the target cell wall or membrane and defensin oligomerization. Indeed, the defensin Nicotiana alata defensin 1 (NaD1) binds to a broad range of membrane phosphatidylinositol phosphates and forms an oligomeric complex with phosphatidylinositol (4,5)-bisphosphate (PIP2) that facilitates membrane lysis of both mammalian tumor and fungal cells. Here, we report that the tomato defensin TPP3 has a unique lipid binding profile that is specific for PIP2 with which it forms an oligomeric complex that is critical for cytolytic activity. Structural characterization of TPP3 by X-ray crystallography and site-directed mutagenesis demonstrated that it forms a dimer in a "cationic grip" conformation that specifically accommodates the head group of PIP2 to mediate cooperative higher-order oligomerization and subsequent membrane permeabilization. These findings suggest that certain plant defensins are innate immune receptors for phospholipids and adopt conserved dimeric configurations to mediate PIP2 binding and membrane permeabilization. This mechanism of innate defense may be conserved across defensins from different species. P lant defensins are small (ϳ5 kDa), cysteine-rich, cationic peptides that belong to the broad class of innate defense molecules known as cationic antimicrobial peptides (CAPs). Plant defensins play a major role in plant innate immunity and have been identified in all analyzed plant species to date, as either constitutively expressed or induced defense molecules that are produced in response to pathogenic attack or environmental stress (1). The tertiary structure of all plant defensins is highly conserved, comprising a triple-stranded antiparallel ␤-sheet and a single ␣-helix stabilized by four disulfide bridges, known as the "cysteine-stabilized alpha-beta" or "CS␣␤" motif (2). Despite this conserved three-dimensional structure, there is a high degree of variation in the primary sequence of plant defensins, particularly at intervening loop regions, which are typically important for activity (3).Many plant defensins have antifungal activity, but other functions have been reported, including antibacterial activity, ion channel blocking, protein synthesis inhibition, and trypsin and ␣-amylase inhibition as well as roles in heavy metal tolerance, plant development, and pollen tube guidance (3-5). They can be divided into two classes based on whether or not a C-terminal propeptide (CTPP) (of ϳ33 amino acids) is present (2, 6). This domain is involved in vacuolar targeting and protects the plant cells from phytotoxicity during transit through the secretory pathway (7). Defensins expressed with the additional CTPP domain are kn...

show abstract

supporting

confidence: 62%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

The Tomato Defensin TPP3 Binds Phosphatidylinositol (4,5)-Bisphosphate via a Conserved Dimeric Cationic Grip Conformation To Mediate Cell Lysis

Baxter

Richter

Lay

et al. 2015

Molecular and Cellular Biology

Self Cite

104

View full text Add to dashboard Cite

show abstract

“…69 NaD1 was solved by X-ray crystallography in complex with PI(4,5)P 2 , revealing the formation of a dimeric 'cationic grip' PI(4,5)P 2 binding pocket, repeated to form an extended oligomeric arch. This interaction was proposed to induce membrane destabilization of target cells, with sitedirected mutagenesis of key lipid-binding residues confirming the requirement of PI(4,5)P 2 for efficient membrane lysis of both Fusarium oxysporum as well as mammalian tumor cells 69,118 (Figure 2i). Similar PI(4,5)P 2 -binding mechanism was also described for the tomato defensin TPP3, which binds specifically to PI(4,5)P 2 and shares the conserved cationic grip binding pocket as NaD1 to mediate cell lysis.…”

Section: Pathogenic Entry Via the Host Extracellular Phospholipid Codementioning

confidence: 71%

The phospholipid code: a key component of dying cell recognition, tumor progression and host–microbe interactions

2015

View full text Add to dashboard Cite

A significant effort is made by the cell to maintain certain phospholipids at specific sites. It is well described that proteins involved in intracellular signaling can be targeted to the plasma membrane and organelles through phospholipid-binding domains. Thus, the accumulation of a specific combination of phospholipids, denoted here as the 'phospholipid code', is key in initiating cellular processes. Interestingly, a variety of extracellular proteins and pathogen-derived proteins can also recognize or modify phospholipids to facilitate the recognition of dying cells, tumorigenesis and host-microbe interactions. In this article, we discuss the importance of the phospholipid code in a range of physiological and pathological processes.

show abstract

“…23,24) These structural studies also report the locations of intermolecular hydrogen bonds to form dimer formation of plant defensin. 23,24) Using SDS-PAGE analysis, it has been reported that AFP1 is capable of forming an oligomeric configuration. 18) In AFP1, the location of residue E5 is corresponds with the position involving the intermolecular hydrogen bonds for dimer formation.…”

Section: Discussionmentioning

confidence: 98%

Purification and cDNA cloning of a defensin in Brassica juncea, its functional expression in Escherichia coli, and assessment of its antifungal activity

et al. 2013

View full text Add to dashboard Cite

We describe the purification, cDNA cloning, and characterization of a defensin, AFP1, in Brassica juncea, which shares 100% amino acid sequence identity with Raphanus sativus defensin (Rs-AFP1) and has a high antifungal activity against Magnaporthe oryzae. The recombinant AFP1 synthesized in Escherichia coli showed thermostability and antifungal activity against a broad spectrum of rice pathogenic fungi. The changes of a negative to positive charge at the surface of AFP1 derived by amino acid substitutions showed more enhanced antifungal activities than the wild-type AFP1.

show abstract

Dimerization of Plant Defensin NaD1 Enhances Its Antifungal Activity

Cited by 69 publications

References 88 publications

The Tomato Defensin TPP3 Binds Phosphatidylinositol (4,5)-Bisphosphate via a Conserved Dimeric Cationic Grip Conformation To Mediate Cell Lysis

The Tomato Defensin TPP3 Binds Phosphatidylinositol (4,5)-Bisphosphate via a Conserved Dimeric Cationic Grip Conformation To Mediate Cell Lysis

The phospholipid code: a key component of dying cell recognition, tumor progression and host–microbe interactions

Purification and cDNA cloning of a defensin in Brassica juncea, its functional expression in Escherichia coli, and assessment of its antifungal activity

Contact Info

Product

Resources

About