Excitement ahead: structure, function and mechanism of snake venom phospholipase A2 enzymes

doi:10.1016/j.toxicon.2003.11.002

Toxicon

Volume 42, Issue 8, December 2003, Pages 827-840

https://doi.org/10.1016/j.toxicon.2003.11.002 Get rights and content

Abstract

Venom phospholipase A₂ (PLA₂) enzymes share similarity in structure and catalytic function with mammalian enzymes. However, in contrast to mammalian enzymes, many are toxic and induce a wide spectrum of pharmacological effects. Thus structure–function relationship of this group of small proteins is subtle, but complex puzzle to protein biochemists, molecular biologists, toxinologists, pharmacologists and physiologists. This review describes the present status of our understanding of their structure, function and mechanism. It was proposed that their unique ability to ‘target’ themselves to a specific organ or tissue is due to their high affinity binding to specific proteins which act as receptors (more precisely, acceptors). This specific binding of PLA₂ is conferred by the presence of a ‘pharmacological site’ on its surface which is independent of the catalytic site. The high affinity interaction of PLA₂ with its acceptor (or target protein) is probably due to the complementarity, in terms of charges, hydrophobicity and van der Waal's contact surfaces, between the pharmacological site and the binding site on the surface of the acceptor protein. Upon binding to the target, the PLA₂ can induce its pharmacological effects by mechanisms either dependent on or independent of its catalytic activity. Because of the unprecedented wide spectrum of specific targeting to various tissues and organs, identification of the pharmacological sites has potential for exploitation in development of novel systems useful for ‘delivering’ specific proteins to a particular target tissue or organ. Thus research in this field will provide a lot of exciting opportunities.

Introduction

Phospholipase A₂ (PLA₂) enzymes hydrolyze glycerophospholipids at the sn-2 position of the glycerol backbone releasing lysophospholipids and fatty acids. They occur ubiquitously in nature as both intracellular and extracellular forms and hydrolyze various phospholipids. They are the most studied among all phospholipases because of their pivotal role in various biological activities. Mammalian PLA₂ enzymes play important role in fertilization (Fry et al., 1992), cell proliferation (Arita et al., 1991), smooth muscle contraction (Nakajima et al., 1992, Sommers et al., 1992), and hypersensitization and chronic inflammatory diseases (Vadas and Pruzanski, 1986, Vadas et al., 1993). They are also important in cellular functions such as signal transduction via biosynthesis of prostaglandins and leukotrienes, and membrane homeostasis including the maintenance of the cellular phospholipid pools and membrane repair through deacylation/reacylation (Verheij et al., 1981, Jain and Berg, 1989, Dennis et al., 1991, Kudo et al., 1993, Dennis, 1994). However, mammalian enzymes are generally nontoxic and fail to induce potent pharmacological effects. On the other hand, snake venom PLA₂ enzymes, in addition to their possible role in the digestion of the prey, exhibit a wide variety of pharmacological effects by interfering in normal physiological processes (Kini, 1997a) (Table 1). Some of the most toxic and potent pharmacologically active components of snake venoms are either PLA₂ enzymes or their protein complexes. For example, all known presynaptic neurotoxins from snake venom are PLA₂ enzymes per se or contain PLA₂ as an integral part (Gubenšek et al., 1997, Bon, 1997). PLA₂ myotoxins are more potent and fast-acting than their nonenzymatic counterparts (Fletcher et al., 1997). The ability to induce pharmacological effects with higher potencies underscores the importance of PLA₂ enzymes in snake venom toxicity.

So far, the amino acid sequences of over 280 PLA₂ enzymes have been determined (Danse et al., 1997, Tan et al., 2003). (A database of snake venom PLA₂ enzymes is available at http://sdmc.lit.org.sg/Templar/DB/snaketoxin_PLA2/index.html). Despite the differences in their pharmacological properties, they share 40–99% identity in their amino acid sequences and hence significant similarity in their three dimensional folding (Scott, 1997). Thus the functional differences among PLA₂ enzymes cannot be easily correlated to their structural differences. The structural similarity makes the structure–function relationships subtle, complicated and challenging. The shared common ability to hydrolyze at the sn-2 position of phospholipids and the lack correlation between enzymatic activity and lethal toxicity or pharmacological potency (Rosenberg, 1997a, Rosenberg, 1997b), make the mechanisms by which snake venom PLA₂ enzymes induce a wide spectrum of pharmacological effects intriguing. A monograph (Kini, 1997b) on snake venom PLA₂ enzymes deals with their structure, function and mechanism. This review provides an overview of the structure–function relationships and the mechanisms of snake venom PLA₂ enzymes and their implications.

Section snippets

Purification

The quality of enzyme preparations is crucial for structure–function and mechanistic studies. Any contamination may contribute significantly to the results; such data could be invalid and may complicate the studies on structure-function and mechanism. The following two factors should be considered during the purification of PLA₂ enzymes from snake venoms: (a) Snake venoms often contain a large number of PLA₂ isoenzymes. For example, Naja naja, Vipera russelli, Trimeresurus flavoviridis,

Catalysis

PLA₂ enzymes are unique hydrolytic enzymes in that they are highly soluble in water but hydrolyze water-insoluble substrate phospholipids. They hydrolyze phospholipids in monomeric, micellar or lipid bilayer phases. They exhibit a large and abrupt increase (up to 10,000-fold) in their catalytic activity when monomeric phospholipids aggregate to form micelles at their critical micellar concentration (Verger and DeHaas, 1973, Verger et al., 1973, Jain and Cordes, 1973a, Jain and Cordes, 1973b,

Pharmacological effects

Snake venom PLA₂ enzymes exhibit a wide variety of pharmacological effects (Table 1). When studying a new enzyme, it is important to examine its pharmacological effects in intact animals, rather than in isolated tissues or in vitro methods. The in vitro studies sometimes show nonspecific effects that are due to the inherent phospholipolytic activity resulting in wrong conclusions. Occasionally, some of the pharmacological effects can be studied only in in vitro systems.

In most cases, snake

Target model and pharmacological specificity

Although a variety of pharmacological effects are induced by PLA₂ enzymes, not all the effects are exhibited by all PLA₂ enzymes. Each enzyme exhibits a specific effect. For example, β-bungarotoxin, a PLA₂ containing toxin, induces a presynaptic effect on nicotinic acetylcholine transmission (Strong et al., 1976) but not glutamate and adrenergic transmission even at high concentrations (Abe et al., 1977). It does not show postsynaptic activity (Yang, 1978), myotoxicity (Fraenkel-Conrat, 1982-83

Enzymatic activity and pharmacological effects

Upon binding to the target protein, PLA₂ enzymes can induce their pharmacological effects through mechanisms that are either dependent on or independent of their enzymatic activity. In the mechanisms that are dependent on enzymatic activity, either the hydrolysis of intact phospholipids or the released products such as lysophospholipids and fatty acids can cause the pharmacological effect (For details, see Kini and Evans, 1989a). The inherent enzymatic activity can cause membrane damage and

Pharmacological sites

PLA₂ enzymes bind to target proteins through specific pharmacological sites (Fig. 1) (Kini and Evans, 1989a). The presence of pharmacological sites is supported by chemical modification studies, polyclonal and monoclonal antibodies and interaction of inhibitors (for reviews, see Yang, 1997, Stiles and Choumet, 1997, Gowda, 1997). Various chemical methods to modify specific amino acid residues have been used to identify these structural features. Despite systematic efforts, it has been difficult

Accelerated evolution of molecular surface

Recently by comparing the structures of 127 snake venom PLA₂ enzymes, we showed that mutational hot spots occur on the surface of this protein molecule (Kini and Chan, 1999). Natural substitutions occur about 2.6–3.5 times greater in fully exposed residues than in the buried residues. As described above, the surface residues are important in molecular recognition of target proteins. Thus, natural substitutions in the surface residues would contribute directly towards modifying the molecular

Future prospects

Snake venom PLA₂ enzymes are small enzymes which cause havoc by interfering in the normal physiological processes of the victim and inducing a variety of pharmacological effects. They provide a great challenge to protein chemists as subtle and complex puzzles in structure-function relationships. A better understanding will contribute to our knowledge of protein–protein interactions, protein targeting and protein engineering and to the development of better targeted delivery systems. Further

Acknowledgements

I thank my colleagues and mentors who ‘supported’ and nurtured at various levels several ideas presented in this chapter. This work is supported by Academic research grants from the National University of Singapore.

References (141)

H Arita et al.
Novel proliferative effect of phospholipase A₂ in Swiss 3T3 cells via specific binding site
J. Biol. Chem.
(1991)
Y Chuman et al.
Regional and accelerated molecular evolution in group I snake venom gland phospholipase A₂ isozymes
Toxicon
(2000)
E Condrea et al.
Role of cobra venom direct lytic factor and Ca²⁺in promoting the activity of snake venom phospholipase A
Biochim. Biophys. Acta
(1970)
A Čopič et al.
Identification and purification of a novel receptor for secretory phospholipase A₂ in porcine cerebral cortex
J. Biol. Chem.
(1999)
V Čurin-Šerbec et al.
Immunological studies of the toxic site in ammodytoxin A
FEBS Lett.
(1991)
E.A Dennis
Diversity of group types, regulation, and function of phospholipase A₂
J. Biol. Chem.
(1994)
D.C Dodds et al.
Neuronal pentraxin receptor, a novel putative integral membrane pentraxin that interacts with neuronal pentraxin 1 and 2 and taipoxin-associated calcium-binding protein 49
J. Biol. Chem.
(1997)
H.J Evans et al.
Isolation of anticoagulant proteins from cobra venom (Naja nigricollis). Identity with phospholipases A₂
J. Biol. Chem.
(1980)
G Faure et al.
Crotoxin acceptor protein isolated from Torpedo electric organ: binding properties to crotoxin by surface plasmon resonance
Toxicon
(2003)
S Forst et al.
Relation between binding and the action of phospholipases A₂ on Escherichia coli exposed to the bactericidal/permeability-increasing protein of neutrophils
Biochim. Biophys. Acta
(1987)

R Gao et al.

Purification and properties of three new phospholipase A₂ isoenzymes from Micropechis ikaheka venom

Biochim. Biophys. Acta

(2001)

P Gopalakrishnakone et al.

Cellular and mitochondrial changes induced in the structure of murine skeletal muscle by crotoxin, a neurotoxic phospholipase A₂ complex

Toxicon

(1984)

M.J Hseu et al.

Purification and partial amino acid sequence of a novel protein of the reticulocalbin family

Biochem. Biophys. Res. Commun.

(1997)

M.J Hseu et al.

Crocalbin: a new calcium-binding protein that is also a binding protein for crotoxin, a neurotoxic phospholipase A₂

FEBS Lett.

(1999)

M Inada et al.

Determinants of the inhibitory action of purified 14-kDa phospholipases A₂ on cell-free prothrombinase complex

J. Biol. Chem.

(1994)

G Ivanovski et al.

The amino acid region 115-119 of ammodytoxins plays an important role in neurotoxicity

Biochem. Biophys. Res. Commun.

(2000)

M.K Jain et al.

The kinetics of interfacial catalysis by phospholipase A₂ and regulation of interfacial activation: hopping versus scooting

Biochim. Biophys. Acta

(1989)

S Kasturi et al.

Purification and characterization of a major phospholipase A₂ from Russell's viper (Vipera russelli) venom

Toxicon

(1989)

R.T Kerns et al.

Targeting of venom phospholipases: the strongly anticoagulant phospholipase A₂ from Naja nigricollis venom binds to coagulation factor Xa to inhibit the prothrombinase complex

Arch. Biochem. Biophys.

(1999)

R.M Kini

Proline brackets and identification of potential functional sites in proteins: toxins to therapeutics

Toxicon

(1998)

R.M Kini et al.

Structure–function relationships of phospholipases: The anticoagulant region of phospholipases A₂

J. Biol. Chem.

(1987)

R.M Kini et al.

A model to explain the pharmacological effects of snake venom phospholipases A₂

Toxicon

(1989)

R.M Kini et al.

The role of enzymatic activity in inhibition of the extrinsic tenase complex by phospholipase A₂ isoenzymes from Naja nigricollis venom

Toxicon

(1995)

R.M Kini et al.

A hypothetical structural role for proline residues in the flanking segments of protein–protein interaction sites

Biochem. Biophys. Res. Commun.

(1995)

R.M Kini et al.

Prediction of potential protein–protein interaction sites from amino acid sequence. Identification of a fibrin polymerization site

FEBS Lett.

(1996)

R.M Kini et al.

Structure function relationships of phospholipases I: prediction of presynaptic neurotoxicity

Toxicon

(1986)

R.M Kini et al.

Amino terminal region three isoenzymes of phospholipases A₂ (TFV PLIa, TFV PLIb AND TFV PLX) from Trimeresurus flavoviridis (habu snake) venom and the complete amino acid sequence of the basic phospholipase, TFV PLX

Toxicon

(1986)

L.L Kirkpatrick et al.

Comparison of Biochemical interactions of the neuronal pentraxins. Neuronal pentraxin (NP) receptor binds to taipoxin and taipoxin-associated calcium-binding protein 49 via NP1 and NP2

J. Biol. Chem.

(2000)

I Križaj et al.

Neuronal receptors for phospholipases A₂ and β-neurotoxicity

Biochimie

(2000)

I Križaj et al.

Primary structure of ammodytoxin C further reveals the toxic site of ammodytoxin

Biochim. Biophys. Acta

(1989)

I Križaj et al.

Ammodytoxin A acceptor in bovine brain synaptic membranes

Toxicon

(1995)

I Križaj et al.

Re-examination of crotoxin-membrane interactions

Toxicon

(1996)

I Kudo et al.

Mammalian non-pancreatic phospholipases A₂

Biochim. Biophys. Acta

(1993)

G Lambeau et al.

Identification and properties of very high affinity brain membrane-binding sites for a neurotoxic phospholipase from the taipan venom

J. Biol. Chem.

(1989)

G Lambeau et al.

Identification and purification of a very high affinity binding protein for toxic phospholipases A₂ in skeletal muscle

J. Biol. Chem.

(1990)

G Lambeau et al.

Structural elements of secretory phospholipases A₂ involved in the binding to M-type receptors

J. Biol. Chem.

(1995)

E.C.T Landucci et al.

Crotoxin induces aggregation of human washed platelets

Toxicon

(1994)

B Lomonte et al.

Neutralizing interaction between heparins and myotoxin II, a lysine 49 phospholipase A₂ from Bothrops asper snake venom. Identification of a heparin-binding and cytolytic toxin region by the use of synthetic peptides and molecular modeling

J. Biol. Chem.

(1994)

B Lomonte et al.

Tyr→Trp-substituted peptide 115-129 of a Lys49 phospholipase A₂ expresses enhanced membrane-damaging activities and reproduces its in vivo myotoxic effect

Biochim. Biophys. Acta.

(1999)

C.M Mounier et al.

Inhibition of prothrombinase by human secretory phospholipase A₂ involves binding to factor Xa

J. Biol. Chem.

(1998)

M Nakajima et al.

Effect of pancreatic type phospholipase A₂ on isolated porcine cerebral arteries via its specific binding sites

FEBS Lett.

(1992)

I Nobuhisa et al.

Accelerated evolution of Trimeresurus okinavensis venom gland phospholipase A₂ isoenzyme-encoding genes

Gene

(1996)

C.E Núñez et al.

Identification of the myotoxic site of the Lys49 phospholipase A₂ from Agkistrodon piscivorus piscivorus snake venom: synthetic C-terminal peptides from Lys49, but not from Asp49 myotoxins, exert membrane-damaging activities

Toxicon

(2001)

T Ogawa et al.

Accelerated evolution of snake venom phospholipase A₂ isozymes for acquisition of diverse physiological functions

Toxicon

(1996)

H Rehm et al.

Binding of β-bungarotoxin to synaptic membrane fractions of chick brain

J. Biol. Chem.

(1982)

T Abe et al.

Isolation and characterization of presynaptically acting neurotoxins from the venom of Bungarus snakes

Eur. J. Biochem.

(1977)

A Alape-Giron et al.

Elapid venom toxins: multiple recruitments of ancient scaffolds

Eur. J. Biochem.

(1999)

E Arrigada et al.

Search for a toxic site in snake venom phospholipases A₂

Arch. Biol. Med. Exp.

(1989)

A.R Black et al.

Solubilization and physical characterization of acceptors for dendrotoxin and β-bungarotoxin from synaptic membranes of rat brain

Biochemistry

(1988)

S.E Blondelle et al.

Hemolytic and antimicrobial activities of the twenty-four individual omission analogues of melittin

Biochemistry

(1991)

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Excitement ahead: structure, function and mechanism of snake venom phospholipase A2 enzymes

Abstract

Introduction

Section snippets

Purification

Catalysis

Pharmacological effects

Target model and pharmacological specificity

Enzymatic activity and pharmacological effects

Pharmacological sites

Accelerated evolution of molecular surface

Future prospects

Acknowledgements

J. Biol. Chem.

Toxicon

Biochim. Biophys. Acta

J. Biol. Chem.

FEBS Lett.

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

Toxicon

Biochim. Biophys. Acta

Biochim. Biophys. Acta

Toxicon

Biochem. Biophys. Res. Commun.

FEBS Lett.

J. Biol. Chem.

Biochem. Biophys. Res. Commun.

Biochim. Biophys. Acta

Toxicon

Arch. Biochem. Biophys.

Toxicon

J. Biol. Chem.

Toxicon

Toxicon

Biochem. Biophys. Res. Commun.

FEBS Lett.

Toxicon

Toxicon

J. Biol. Chem.

Biochimie

Biochim. Biophys. Acta

Toxicon

Toxicon

Biochim. Biophys. Acta

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

Toxicon

J. Biol. Chem.

Biochim. Biophys. Acta.

J. Biol. Chem.

FEBS Lett.

Gene

Toxicon

Toxicon

J. Biol. Chem.

Isolation and characterization of presynaptically acting neurotoxins from the venom of Bungarus snakes

Eur. J. Biochem.

Elapid venom toxins: multiple recruitments of ancient scaffolds

Eur. J. Biochem.

Search for a toxic site in snake venom phospholipases A2

Arch. Biol. Med. Exp.

Solubilization and physical characterization of acceptors for dendrotoxin and β-bungarotoxin from synaptic membranes of rat brain

Biochemistry

Hemolytic and antimicrobial activities of the twenty-four individual omission analogues of melittin

Biochemistry

Excitement ahead: structure, function and mechanism of snake venom phospholipase A₂ enzymes

Search for a toxic site in snake venom phospholipases A₂