MilliporeSigma
  • Glycan specificity of a testis-specific lectin chaperone calmegin and effects of hydrophobic interactions.

Glycan specificity of a testis-specific lectin chaperone calmegin and effects of hydrophobic interactions.

Biochimica et biophysica acta (2014-04-29)
Masafumi Sakono, Akira Seko, Yoichi Takeda, Jun-ichi Aikawa, Masakazu Hachisu, Akihiko Koizumi, Kohki Fujikawa, Yukishige Ito
ABSTRACT

Testis-specific chaperone calmegin is required for the generation of normal spermatozoa. Calmegin is known to be a homologue of endoplasmic reticulum (ER) residing lectin chaperone calnexin. Although functional similarity between calnexin and calmegin has been predicted, detailed information concerned with substrate recognition by calmegin, such as glycan specificity, chaperone function and binding affinity, are obscure. In this study, biochemical properties of calmegin and calnexin were compared using synthetic glycans and glycosylated or non-glycosylated proteins as substrates. Whereas their amino acid sequences are quite similar to each other, a certain difference in secondary structures was indicated by circular dichroism (CD) spectrum. While both of them inhibited protein heat-aggregation to a similar extent, calnexin exhibited a higher ability to facilitate protein folding. Similarly to calnexin, calmegin preferentially recognizes monoglucosylated glycans such as Glc1Man9GlcNAc2 (G1M9). While the surface hydrophobicity of calmegin was higher than that of calnexin, calnexin showed stronger binding to substrate. We reasoned that lectin activity, in addition to hydrophobic interaction, contributes to this strong affinity between calnexin and substrate. Although their similarity in carbohydrate binding specificities is high, there seems to be some differences in the mode of substrate recognition between calmegin and calnexin. Properties of calmegin as a lectin-chaperone were revealed in comparison with calnexin.

MATERIALS
Product Number
Brand
Product Description

Supelco
Residual Solvent - Acetonitrile, Pharmaceutical Secondary Standard; Certified Reference Material
Supelco
DL-Dithiothreitol solution, 1 M in H2O
Supelco
Calcium ion solution for ISE, 0.1 M Ca, analytical standard (for ion-selective electrodes)
Sigma-Aldrich
Acetonitrile solution, contains 0.1 % (v/v) trifluoroacetic acid, suitable for HPLC
Sigma-Aldrich
Acetonitrile solution, contains 0.05 % (v/v) trifluoroacetic acid
Sigma-Aldrich
Acetonitrile solution, contains 0.1 % (v/v) formic acid, suitable for HPLC
Sigma-Aldrich
Calcium chloride solution, BioUltra, for molecular biology, ~1 M in H2O
Sigma-Aldrich
Trizma® hydrochloride, pH 3.5-5.0 (0.5 M in H2O), BioXtra, ≥99.0% (titration)
Sigma-Aldrich
Calcium chloride
Sigma-Aldrich
Guanidine hydrochloride solution, Colorless liquid, 7.8 - 8.3 M, pH- 4.5 - 5.5
Sigma-Aldrich
Guanidine hydrochloride solution, BioUltra, ~8 M in H2O
Sigma-Aldrich
DL-Dithiothreitol solution, BioUltra, for molecular biology, ~1 M in H2O
Sigma-Aldrich
Acetonitrile solution, contains 0.05 % (w/v) ammonium formate, 5 % (v/v) water, 0.1 % (v/v) formic acid, suitable for HPLC
Sigma-Aldrich
Acetonitrile solution, contains 10.0% acetone, 0.05% formic acid, 40.0% 2-propanol
SAFC
Guanidine hydrochloride
Sigma-Aldrich
Acetonitrile, suitable for HPLC-GC, ≥99.8% (GC)
Sigma-Aldrich
Acetonitrile, suitable for HPLC, gradient grade, ≥99.9%
Sigma-Aldrich
Acetonitrile, suitable for HPLC, gradient grade, ≥99.9%
Sigma-Aldrich
Acetonitrile, HPLC Plus, ≥99.9%
Sigma-Aldrich
Calcium carbonate, puriss., meets analytical specification of Ph. Eur., BP, USP, FCC, E170, precipitated, 98.5-100.5% (based on anhydrous substance)
Sigma-Aldrich
Acetonitrile, suitable for DNA synthesis, ≥99.9% (GC)
Sigma-Aldrich
Calcium carbonate, ACS reagent, ≥99.0%, powder
Sigma-Aldrich
Acetonitrile, biotech. grade, ≥99.93%
Sigma-Aldrich
Acetonitrile, ACS reagent, ≥99.5%
Supelco
Acetonitrile, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Acetonitrile, electronic grade, 99.999% trace metals basis
Supelco
Calcium carbonate, Pharmaceutical Secondary Standard; Certified Reference Material
USP
Residual Solvent Class 2 - Acetonitrile, United States Pharmacopeia (USP) Reference Standard
USP
Calcium Carbonate (AS), United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Calcium chloride, AnhydroBeads, −10 mesh, ≥99.9% trace metals basis