Modulation of conotoxin structure and function is achieved through a multienzyme complex in the venom glands of cone snails
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Modulation of conotoxin structure and function is achieved through a multienzyme complex in the venom glands of cone snails. / Safavi-Hemami, Helena; Gorasia, Dhana G; Steiner, Andrew M; Williamson, Nicholas A; Karas, John A; Gajewiak, Joanna; Olivera, Baldomero M; Bulaj, Grzegorz; Purcell, Anthony W.
I: The Journal of Biological Chemistry, Bind 287, Nr. 41, 05.10.2012, s. 34288-303.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Modulation of conotoxin structure and function is achieved through a multienzyme complex in the venom glands of cone snails
AU - Safavi-Hemami, Helena
AU - Gorasia, Dhana G
AU - Steiner, Andrew M
AU - Williamson, Nicholas A
AU - Karas, John A
AU - Gajewiak, Joanna
AU - Olivera, Baldomero M
AU - Bulaj, Grzegorz
AU - Purcell, Anthony W
PY - 2012/10/5
Y1 - 2012/10/5
N2 - The oxidative folding of large polypeptides has been investigated in detail; however, comparatively little is known about the enzyme-assisted folding of small, disulfide-containing peptide substrates. To investigate the concerted effect of multiple enzymes on the folding of small disulfide-rich peptides, we sequenced and expressed protein-disulfide isomerase (PDI), peptidyl-prolyl cis-trans isomerase, and immunoglobulin-binding protein (BiP) from Conus venom glands. Conus PDI was shown to catalyze the oxidation and reduction of disulfide bonds in two conotoxins, α-GI and α-ImI. Oxidative folding rates were further increased in the presence of Conus PPI with the maximum effect observed in the presence of both enzymes. In contrast, Conus BiP was only observed to assist folding in the presence of microsomes, suggesting that additional co-factors were involved. The identification of a complex between BiP, PDI, and nascent conotoxins further suggests that the folding and assembly of conotoxins is a highly regulated multienzyme-assisted process. Unexpectedly, all three enzymes contributed to the folding of the ribbon isomer of α-ImI. Here, we identify this alternative disulfide-linked species in the venom of Conus imperialis, providing the first evidence for the existence of a "non-native" peptide isomer in the venom of cone snails. Thus, ER-resident enzymes act in concert to accelerate the oxidative folding of conotoxins and modulate their conformation and function by reconfiguring disulfide connectivities. This study has evaluated the role of a number of ER-resident enzymes in the folding of conotoxins, providing novel insights into the enzyme-guided assembly of these small, disulfide-rich peptides.
AB - The oxidative folding of large polypeptides has been investigated in detail; however, comparatively little is known about the enzyme-assisted folding of small, disulfide-containing peptide substrates. To investigate the concerted effect of multiple enzymes on the folding of small disulfide-rich peptides, we sequenced and expressed protein-disulfide isomerase (PDI), peptidyl-prolyl cis-trans isomerase, and immunoglobulin-binding protein (BiP) from Conus venom glands. Conus PDI was shown to catalyze the oxidation and reduction of disulfide bonds in two conotoxins, α-GI and α-ImI. Oxidative folding rates were further increased in the presence of Conus PPI with the maximum effect observed in the presence of both enzymes. In contrast, Conus BiP was only observed to assist folding in the presence of microsomes, suggesting that additional co-factors were involved. The identification of a complex between BiP, PDI, and nascent conotoxins further suggests that the folding and assembly of conotoxins is a highly regulated multienzyme-assisted process. Unexpectedly, all three enzymes contributed to the folding of the ribbon isomer of α-ImI. Here, we identify this alternative disulfide-linked species in the venom of Conus imperialis, providing the first evidence for the existence of a "non-native" peptide isomer in the venom of cone snails. Thus, ER-resident enzymes act in concert to accelerate the oxidative folding of conotoxins and modulate their conformation and function by reconfiguring disulfide connectivities. This study has evaluated the role of a number of ER-resident enzymes in the folding of conotoxins, providing novel insights into the enzyme-guided assembly of these small, disulfide-rich peptides.
KW - Animals
KW - Conotoxins/biosynthesis
KW - Conus Snail/enzymology
KW - Exocrine Glands/enzymology
KW - Heat-Shock Proteins/metabolism
KW - Multienzyme Complexes/metabolism
KW - Oxidation-Reduction
KW - Peptidylprolyl Isomerase/metabolism
KW - Protein Disulfide-Isomerases/metabolism
KW - Protein Folding
KW - Structure-Activity Relationship
U2 - 10.1074/jbc.M112.366781
DO - 10.1074/jbc.M112.366781
M3 - Journal article
C2 - 22891240
VL - 287
SP - 34288
EP - 34303
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 41
ER -
ID: 232824815