Secretory Phospholipase A2

Murakami, Makoto; Kudo, Ichiro

doi:10.1248/bpb.27.1158

Cited by 120 publications

(117 citation statements)

References 93 publications

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“…The shape of the CD spectrum of the chimeric protein was different from those of the group IB and IIA PLA 2 s, however. The CD spectrum of the N10IIA/IB PLA 2 222 are associated with deviations of the ␣-helix structure from a standard, rigid helix geometry, e.g. by formation of coiled-coil structures (27,28) or distorted helices (29).…”

Section: Resultsmentioning

confidence: 99%

“…The Structure of Membrane-bound Chimeric PLA 2 as Compared with That of the hIBPLA 2 -As described in the Introduction in more detail, group IB PLA 2 s have been shown to acquire a more rigid structure upon binding to phospholipid micelles or membranes, involving primarily the N-terminal ␣-helix (9 -13), whereas membrane binding of group IIA PLA 2 s results in more flexible ␣-helices (14 -17). Because the N-terminal ␣-helix of group I/II PLA 2 s is a crucial structural component of the membrane binding face of these enzymes, it is important to identify its contribution to changes in the secondary or dynamic structure of PLA 2 s during membrane binding.…”

Section: Resultsmentioning

confidence: 99%

“…The ratios of apparent extinction coefficient of 13 C-labeled and unlabeled helices of both the hIBPLA 2 and the chimeric PLA 2 were estimated as ⑀ 13C /⑀ 12C ϭ I 13C n 12C /I 12C n 13C , where I and n are the integrated amide I intensities and the numbers of amino acid residues for corresponding helices, respectively. The corrected, polarization-independent ATR-FTIR spectra were used for such analysis, which indicated that ⑀ 13C /⑀ 12C ϭ 0.54 for hIBPLA 2 and ⑀ 13C /⑀ 12C ϭ 0.67 for the chimeric protein. Increased absorptivity of the amide I mode of unlabeled versus 13 C-labeled helices was detected before for synthetic 32-mer peptides containing stretches of three consecutive 13 C-labeled residues (38).…”

Section: Resultsmentioning

confidence: 99%

“…N-(Fluorescein-5-thiocarbamoyl)-1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (FPE) was from Invitrogen. The N-terminal decapeptides of hIBPLA 2 and hIIAPLA 2 , Ac-Ala-Val-Trp-Gln-Phe-Arg-Lys-Met-Ile-Lys-NH 2 (N10hIB) and Ac-Asn-Leu-Val-Asn-Phe-His-Arg-Met-Ile-Lys-NH 2 (N10hIIA), respectively, were synthesized by Advanced ChemTech (Louisville, KY) and were Ն99% pure, as confirmed by high pressure liquid chromatography and mass spectrometry. C-terminally thioesterified peptides, containing a -COSCH 2 COOH group at the C terminus, were synthesized by SynPep Corp. (Dublin, CA) and were 99% pure.…”

Section: Methodsmentioning

confidence: 99%

“…Segmental isotope labeling also allowed determination of the angular orientation of membrane-bound proteins by polarized attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Observed conformational differences in the N-terminal and internal helices of hIBPLA 2 and of the chimeric PLA 2 (N10IIA/IB) containing the first 10 residues of hIIAPLA 2 and the rest from hIBPLA 2 indicate an important role for the N-terminal helix as a domain that regulates structural transformations during interfacial activation and facilitates proper membrane binding of group I/II PLA 2 s.…”

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confidence: 99%

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Evidence for the Regulatory Role of the N-terminal Helix of Secretory Phospholipase A2 from Studies on Native and Chimeric Proteins

Qin

Pande

Nemec

et al. 2005

Journal of Biological Chemistry

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The phospholipase A 2 (PLA 2 ) enzymes are activated by binding to phospholipid membranes. Although the N-terminal ␣-helix of group I/II PLA 2 s plays an important role in the productive mode membrane binding of the enzymes, its role in the structural aspects of membrane-induced activation of PLA 2 s is not well understood. In order to elucidate membrane-induced conformational changes in the N-terminal helix and in the rest of the PLA 2 , we have created semisynthetic human group IB PLA 2 in which the N-terminal decapeptide is joined with the 13 C-labeled fragment, as well as a chimeric protein containing the N-terminal decapeptide from human group IIA PLA 2 joined with a 13 C-labeled fragment of group IB PLA 2 . Infrared spectral resolution of the unlabeled and 13 C-labeled segments suggests that the N-terminal helix of membranebound IB PLA 2 has a more rigid structure than the other helices. On the other hand, the overall structure of the chimeric PLA 2 is more rigid than that of the IB PLA 2 , but the N-terminal helix is more flexible. A combination of homology modeling and polarized infrared spectroscopy provides the structure of membrane-bound chimeric PLA 2 , which demonstrates remarkable similarity but also distinct differences compared with that of IB PLA 2 . Correlation is delineated between structural and membrane binding properties of PLA 2 s and their N-terminal helices. Altogether, the data provide evidence that the N-terminal helix of group I/II PLA 2 s acts as a regulatory domain that mediates interfacial activation of these enzymes.Enzymes of the phospholipase A 2 (PLA 2 ) 2 family hydrolyze the sn-2 ester bond of diacylglycerophospholipids and thus initiate the biosynthesis of lipid-derived mediators, such as eicosanoids and platelet-activating factor, which are potent mediators of inflammation, allergy, and tumorigenesis (1-3). These enzymes are divided into several groups and subgroups based on their amino acid sequences, tissue distribution, and functional features (1, 2).PLA 2 s gain their full activity only when they bind to phospholipid micelles or membranes, an effect known as interfacial activation (4 -6). The molecular mechanism of interfacial activation has been the subject of debate over several decades. Initially, similarities of crystal structures of PLA 2 s with and without bound substrate mimics argued against conformational changes in the enzymes during interfacial activation (4). Later, the interfacially activated form of group IB PLA 2 was modeled by anion-mediated dimers (7), which revealed significant conformational changes compared with "inactive" monomeric forms, mainly involving the loop that has the functionally important Tyr 69 , and the presence of an assisting water molecule (8). Several spectroscopic studies also identified conformational changes in group IB and IIA PLA 2 s upon binding to phospholipid micelles or membranes. Fluorescence studies indicated that the N-terminal helix of porcine group IB PLA 2 becomes rigid upon enzyme-substrate complex formation at the m...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Evidence for the Regulatory Role of the N-terminal Helix of Secretory Phospholipase A2 from Studies on Native and Chimeric Proteins

Qin

Pande

Nemec

et al. 2005

Journal of Biological Chemistry

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Toxicodynamic Interactions

Philip¹,

Anand²,

Mehendale³

2010

Principles and Practice of Mixtures Toxicology

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Phospholipases A₂: structure and function

Wilton

2005

Eur. J. Lipid Sci. Technol.

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Phospholipases A 2 (PLA 2 ) are an example of peripheral membrane proteins that must first bind to the phospholipid interface to allow phospholipid hydrolysis to occur. The interfacial (membrane) binding step plays a crucial role in the biological function of the enzyme and membrane affinity may be determined both by the phospholipid composition of the membrane and the properties of the interfacial binding surface of the protein. There are now three major categories of these enzymes, secreted PLA 2 (sPLA 2 ), cytosolic PLA 2 (cPLA 2 ) and Ca 2+ -independent PLA 2 (iPLA 2 ). The structure and function of each category is discussed highlighting how both membrane binding and phospholipid substrate specificity may contribute to the overall functions of these enzymes.

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Secretory Phospholipase A2

Cited by 120 publications

References 93 publications

Evidence for the Regulatory Role of the N-terminal Helix of Secretory Phospholipase A2 from Studies on Native and Chimeric Proteins

Evidence for the Regulatory Role of the N-terminal Helix of Secretory Phospholipase A2 from Studies on Native and Chimeric Proteins

Toxicodynamic Interactions

Phospholipases A₂: structure and function

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Secretory Phospholipase A2

Cited by 120 publications

References 93 publications

Evidence for the Regulatory Role of the N-terminal Helix of Secretory Phospholipase A2 from Studies on Native and Chimeric Proteins

Evidence for the Regulatory Role of the N-terminal Helix of Secretory Phospholipase A2 from Studies on Native and Chimeric Proteins

Toxicodynamic Interactions

Phospholipases A2: structure and function

Contact Info

Product

Resources

About

Phospholipases A₂: structure and function