Engineering of caseins and modulation of their structures and interactions.
Beta-casein (beta-CN) is a milk protein widely used in food industries because of its mild emulsifying properties due to its amphiphilicity. However, the elements determining its micellization behavior in solution and interfacial behavior at the air-water interface are not well known. In order to study how the forced dimerisation influences functional properties of beta-CN, recombinant wild-type beta-CN was produced and distal cysteinylated forms of recombinant beta-CN were engineered. We show that 1) cysteinylated beta-CN formed mainly dimers bridged by disulfide bonds; 2) the process of dimerization adds to the micellization process with temperature and is poorly reversible; 3) covalent disulfide linkage forms at the air-water interface at a lower temperature than in bulk. In conclusion, the location of the cysteinylation in the C-terminus or N-terminus or both is of importance for the properties of beta-CN.
Gaudin
Jean-Charles
JC
UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France.
Le Parc
Annabelle
A
UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France.
Castrec
Benoit
B
UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France.
Ropers
Marie-Hélène
MH
UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France.
Choiset
Yvan
Y
UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France.
Shchutskaya
Juliya
J
UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France; Belozersky Institute of Physico-Chemical Biology, Moscow State University, Lenin's Hills, Moscow, 119992, Russia.
Yousefi
Reza
R
UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France; Department of Biology, College of Sciences, Shiraz University, Shiraz, 71454, Iran.
Muronetz
Vladimir I
VI
Belozersky Institute of Physico-Chemical Biology, Moscow State University, Lenin's Hills, Moscow, 119992, Russia.
Zuev
Yuri
Y
Kazan Institute of Biochemistry and Biophysics, Kazan, P.O. Box 30, 420111, Russia.
Chobert
Jean-Marc
JM
UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France.
Haertlé
Thomas
T
UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France. Electronic address: haertle@nantes.inra.fr.
D000595:Amino Acid Sequence; D001483:Base Sequence; D002364:Caseins / Q000737:chemistry* / Q000378:metabolism; D017931:DNA Primers; D004220:Disulfides / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D011487:Protein Conformation; D015202:Protein Engineering; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship
D002364:Caseins; D017931:DNA Primers; D004220:Disulfides