title: Packing density of glycolipid biosurfactant monolayers give a significant effect on their binding affinity toward immunoglobulin G.
abstract: Mannosylerythritol lipid-A (MEL-A) is one of the most promising glycolipid biosurfactants, and abundantly produced by Pseudozyma yeasts. MEL-A gives not only excellent self-assembling properties but also a high binding affinity toward human immunoglobulin G (HIgG). In this study, three kinds of MEL-A were prepared from methyl myristate [MEL-A (m)], olive oil [MEL-A (o)], and soybean oil [MEL-A (s)], and the effect of interfacial properties of each MEL-A monolayer on the binding affinity toward HIgG was investigated using surface plasmon resonance (SPR) and the measurement of surface pressure (pi)-area (A) isotherms. Based on GC-MS analysis, the main fatty acids were C(8) and C(10) acids in all MEL-A, and the content of unsaturated fatty acids was 0% for MEL-A (m), 9.1% for MEL-A (o), 46.3% for MEL-A (s), respectively. Interestingly, the acid content significantly influenced on their binding affinity, and the monolayer of MEL-A (o) gave a higher binding affinity than that of MEL-A (m) and MEL-A (s). Moreover, the mixed MEL-A (o)/ MEL-A (s) monolayer prepared from 1/1 molar ratio, which comprised of 27.8% of unsaturated fatty acids, indicated the highest binding affinity. At the air/water interface, MEL-A (o) monolayer exhibited a phase transition at 13 degrees C from a liquid condensed monolayer to a liquid expanded monolayer, and the area per molecule significantly expanded above 13 degrees C, while the amount of HIgG bound to the liquid expanded monolayer was much higher than that bound to liquid condensed monolayer. The binding affinity of MEL-A toward HIgG is thus likely to closely relate to the monolayer packing density, and may be partly controlled by temperature.
authors.affiliation: Research Institute for Innovation in Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Imura
authors.forename: Yuma
authors.initials: Y
authors.lastname: Masuda
authors.forename: Seya
authors.initials: S
authors.lastname: Ito
authors.forename: Wannasiri
authors.initials: W
authors.lastname: Worakitkanchanakul
authors.forename: Tomotake
authors.initials: T
authors.lastname: Morita
authors.forename: Tokuma
authors.initials: T
authors.lastname: Fukuoka
authors.forename: Hideki
authors.initials: H
authors.lastname: Sakai
authors.forename: Masahiko
authors.initials: M
authors.lastname: Abe
authors.forename: Dai
authors.initials: D
authors.lastname: Kitamoto
mesh_terms: D006017:Glycolipids / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D019814:Myristic Acid / Q000737:chemistry; D000069463:Olive Oil; D010938:Plant Oils / Q000737:chemistry; D011485:Protein Binding; D013024:Soybean Oil / Q000737:chemistry; D020349:Surface Plasmon Resonance / Q000379:methods; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
chemical_list: D006017:Glycolipids; D007074:Immunoglobulin G; D000069463:Olive Oil; D010938:Plant Oils; D013501:Surface-Active Agents; C439671:mannosylerythritol lipid; D019814:Myristic Acid; D013024:Soybean Oil