7eka | pdb_00007eka
crystal structure of epigallocatechin binding with alpha-lactalbumin
Structural highlights
FunctionLALBA_BOVIN Regulatory subunit of lactose synthase, changes the substrate specificity of galactosyltransferase in the mammary gland making glucose a good acceptor substrate for this enzyme. This enables LS to synthesize lactose, the major carbohydrate component of milk. In other tissues, galactosyltransferase transfers galactose onto the N-acetylglucosamine of the oligosaccharide chains in glycoproteins. Publication Abstract from PubMedImproving the stability and bioavailability of catechins is of great importance. Epigallocatechin (EGC), the major catechin in green tea, is a potent antioxidant with numerous attributed health benefits. However, the low permeability and stability limit its enrichment in the diet for preventive medicine. In this study, we explored the interaction of EGC and alpha-lactalbumin by spectroscopic, thermodynamic, and crystallographic methods. The isothermal titration calorimetry experiments elucidated that alpha-lactalbumin binds to EGC at a ratio of 1:1 with a low affinity of (4.01 +/- 0.11) x 10(5) M(-1). A crystal structure solved at a high resolution (1.2 A) provided direct evidence for the weak interaction between EGC and alpha-lactalbumin at an atomic level. The novel binding site was discovered at the exterior surface of alpha-lactalbumin for the first time, supporting a new binding behavior. Consequently, our results demonstrated that the binding of alpha-lactalbumin to EGC could protect EGC against light-induced, thermal-induced, and pH-induced damage. More importantly, the formed complex has better bioaccessibility than unbound EGC, which was approved by a cell absorption experiment. Such research is beneficial for designing protein-based nanocarriers for polyphenols. Weak Binding of Epigallocatechin to alpha-Lactalbumin Greatly Improves Its Stability and Uptake by Caco-2 Cells.,Ma J, Yao Q, Chen X, Lv C, Zang J, Zhao G J Agric Food Chem. 2021 Aug 4;69(30):8482-8491. doi: 10.1021/acs.jafc.1c03427. , Epub 2021 Jul 21. PMID:34286590[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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