Structural insights into the loss of catalytic competence in pectate lyase activity at low pH

TY - JOUR

T1 - Structural insights into the loss of catalytic competence in pectate lyase activity at low pH

AU - Ali, Salyha

AU - Søndergaard, Chresten Rauff

AU - Teixeira, Susana

AU - Pickersgill, Richard W.

N1 - Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

PY - 2015/10/24

Y1 - 2015/10/24

N2 - Pectate lyase, a family 1 polysaccharide lyase, catalyses cleavage of the α-1,4 linkage of the polysaccharide homogalacturonan via an anti β-elimination reaction. In the Michaelis complex two calcium ions bind between the C6 carboxylate of the d-galacturonate residue and enzyme aspartates at the active centre (+1 subsite), they withdraw electrons acidifying the C5 proton facilitating its abstraction by the catalytic arginine. Here we show that activity is lost at low pH because protonation of aspartates results in the loss of the two catalytic calcium-ions causing a profound failure to correctly organise the Michaelis complex.

AB - Pectate lyase, a family 1 polysaccharide lyase, catalyses cleavage of the α-1,4 linkage of the polysaccharide homogalacturonan via an anti β-elimination reaction. In the Michaelis complex two calcium ions bind between the C6 carboxylate of the d-galacturonate residue and enzyme aspartates at the active centre (+1 subsite), they withdraw electrons acidifying the C5 proton facilitating its abstraction by the catalytic arginine. Here we show that activity is lost at low pH because protonation of aspartates results in the loss of the two catalytic calcium-ions causing a profound failure to correctly organise the Michaelis complex.

U2 - 10.1016/j.febslet.2015.09.014

DO - 10.1016/j.febslet.2015.09.014

M3 - Journal article

C2 - 26420545

SN - 0014-5793

VL - 589

SP - 3242

EP - 3246

JO - F E B S Letters

JF - F E B S Letters

IS - 21

ER -