TY - JOUR

T1 - Efficient secretory expression of functional barley limit dextrinase inhibitor by high cell-density fermentation of Pichia pastoris

A1 - Jensen,Johanne Mørch

A1 - Vester-Christensen,Malene Bech

A1 - Møller,Marie Sofie

A1 - Bønsager,Birgit Christine

A1 - Christensen,Hans Erik Mølager

A1 - Abou Hachem,Maher

A1 - Svensson,Birte

AU - Jensen,Johanne Mørch

AU - Vester-Christensen,Malene Bech

AU - Møller,Marie Sofie

AU - Bønsager,Birgit Christine

AU - Christensen,Hans Erik Mølager

AU - Abou Hachem,Maher

AU - Svensson,Birte

PB - Academic Press

PY - 2011

Y1 - 2011

N2 - The limit dextrinase inhibitor (LDI) from barley seeds acts specifically on limit dextrinase (LD), an endogenous starch debranching enzyme. LDI is a 14kDa hydrophobic protein containing four disulfide bonds and one unpaired thiol group previously found to be either glutathionylated or cysteinylated. It is a member of the so-called CM-protein family that includes α-amylase and serine protease inhibitors, which have been extremely challenging to produce recombinantly in functional form and in good yields. Here, LDI is produced in very high yields by secretory expression by Pichia pastoris applying high cell-density fermentation in a 5L fed-batch bioreactor. Thus about 200mg of LDI, which showed twofold higher inhibitory activity towards LD than LDI from barley seeds, was purified from 1L of culture supernatant by His-tag affinity chromatography and gel filtration. Electrospray ionization mass spectrometry verified the identity of the produced glutathionylated LDI-His6. At a 1:1M ratio the recombinant LDI completely inhibited hydrolysis of pullulan catalyzed by 5–10nM LD. LDI retained stability in the pH 2–12 range and at pH 6.5 displayed a half-life of 53 and 33min at 90 and 93°C, respectively. The efficient heterologous production of LDI suggests secretory expression by P. pastoris to be a promising strategy to obtain other recombinant CM-proteins.

AB - The limit dextrinase inhibitor (LDI) from barley seeds acts specifically on limit dextrinase (LD), an endogenous starch debranching enzyme. LDI is a 14kDa hydrophobic protein containing four disulfide bonds and one unpaired thiol group previously found to be either glutathionylated or cysteinylated. It is a member of the so-called CM-protein family that includes α-amylase and serine protease inhibitors, which have been extremely challenging to produce recombinantly in functional form and in good yields. Here, LDI is produced in very high yields by secretory expression by Pichia pastoris applying high cell-density fermentation in a 5L fed-batch bioreactor. Thus about 200mg of LDI, which showed twofold higher inhibitory activity towards LD than LDI from barley seeds, was purified from 1L of culture supernatant by His-tag affinity chromatography and gel filtration. Electrospray ionization mass spectrometry verified the identity of the produced glutathionylated LDI-His6. At a 1:1M ratio the recombinant LDI completely inhibited hydrolysis of pullulan catalyzed by 5–10nM LD. LDI retained stability in the pH 2–12 range and at pH 6.5 displayed a half-life of 53 and 33min at 90 and 93°C, respectively. The efficient heterologous production of LDI suggests secretory expression by P. pastoris to be a promising strategy to obtain other recombinant CM-proteins.

KW - Pullulan

KW - High stability

KW - Fed-batch bioreactor fermentation

KW - Limit dextrinase inhibitor

KW - Electrospray ionization mass spectrometry

U2 - 10.1016/j.pep.2011.04.009

DO - 10.1016/j.pep.2011.04.009

JO - Protein Expression and Purification

JF - Protein Expression and Purification

SN - 1046-5928

IS - 2

VL - 79

SP - 217

EP - 222

ER -