Formation of amyloid-like fibrils upon limited proteolysis of bovine α-lactalbumin

TY - JOUR

T1 - Formation of amyloid-like fibrils upon limited proteolysis of bovine α-lactalbumin

AU - Otte, Jeanette

AU - Ipsen, Richard

AU - Bauer, Rogert

AU - Bjerrum, Morten J.

AU - Waninge, Rianne

PY - 2005/3/1

Y1 - 2005/3/1

N2 - Bovine α-lactalbumin (α-LA) (10 g L-1) was incubated with a protease from Bacillus licheniformis at pH 7.5 and 50°C. The reaction was biphasic consisting of an initial hydrolysis of intact α-LA and formation of dimers from large hydrolysis products within 60 min followed by aggregation of dimers into aggregates of 500 kDa. The aggregates consisted primarily of fibrillar strands with a diameter of 5 nm. Formation of these strands was accompanied by a change in secondary structure towards higher β-sheet content and strong binding of thioflavin, features shared with amyloidal fibrils. The main components in these fibrils were fragments of 8.8 and 9.8 kDa shown to occur in a monomer-dimer equilibrium. These fragments were identified and a molecular mechanism involving side-by-side assembly of dimers of these fragments into fibrils is proposed.

AB - Bovine α-lactalbumin (α-LA) (10 g L-1) was incubated with a protease from Bacillus licheniformis at pH 7.5 and 50°C. The reaction was biphasic consisting of an initial hydrolysis of intact α-LA and formation of dimers from large hydrolysis products within 60 min followed by aggregation of dimers into aggregates of 500 kDa. The aggregates consisted primarily of fibrillar strands with a diameter of 5 nm. Formation of these strands was accompanied by a change in secondary structure towards higher β-sheet content and strong binding of thioflavin, features shared with amyloidal fibrils. The main components in these fibrils were fragments of 8.8 and 9.8 kDa shown to occur in a monomer-dimer equilibrium. These fragments were identified and a molecular mechanism involving side-by-side assembly of dimers of these fragments into fibrils is proposed.

KW - α-Lactalbumin

KW - Amyloid fibrils

KW - Assembly

KW - Fragments

KW - Proteolysis

UR - http://www.scopus.com/inward/record.url?scp=12344306647&partnerID=8YFLogxK

U2 - 10.1016/j.idairyj.2004.07.004

DO - 10.1016/j.idairyj.2004.07.004

M3 - Journal article

AN - SCOPUS:12344306647

SN - 0958-6946

VL - 15

SP - 219

EP - 229

JO - International Dairy Journal

JF - International Dairy Journal

IS - 3

ER -