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Size‐dependent dextran loading in protein nanotube with an interior wall of concanavalin A
Author(s) -
Shiraishi Yuta,
Akiyama Motofusa,
Sato Takaaki,
Hattori Minoru,
Komatsu Teruyuki
Publication year - 2014
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.3299
Subject(s) - concanavalin a , dextran , materials science , fluorescein isothiocyanate , aqueous solution , biophysics , human serum albumin , chromatography , chemistry , fluorescence , biochemistry , organic chemistry , physics , quantum mechanics , in vitro , biology
This paper describes the synthesis and structure of protein nanotube (NT) with a lectin interior surface and its size‐dependent dextran loading ability in aqueous medium. The NTs were prepared using an alternating layer‐by‐layer build‐up assembly of poly‐ l ‐arginine (PLA) and human serum albumin (HSA) in a track‐etched polycarbonate (PC) membrane (pore diameter, 400 nm), subsequently coating concanavalin A (ConA) as the last layer. Dissolution of the PC template yielded (PLA/HSA) 2 PLA/ConA NTs with 419 ± 14 nm outer diameter and 50 ± 7 nm wall thickness. In a 2‐[4‐(2‐hydroxyethyl)‐1‐piperazinyl]ethanesulfonic acid (HEPES) buffered solution, the NTs captured fluorescein isothiocyanate (FITC)‐labeled dextran [molecular weight 4 kDa, FITC‐Dex(4k)] efficiently into the pores. The ratio of the bound FITC‐Dex(4kDa)/ConA was estimated to be 2.1 (mol/mol). Two of four glucosyl‐residue binding sites of ConA on the wall presumably faced to the aqueous inner phase of the tube, and they can bind FITC‐Dex(4k). On the one hand, only half amount of FITC‐Dex was loaded into the channels when the molecular weight of the dextran is greater than 20 kDa. Small‐angle X‐ray scattering measurements revealed that the radius of gyration ( R g ) of the FITC‐Dex(4k) is 1.45 nm (5.0 mg/ml), which is satisfactorily small to interact with the each binding site of ConA independently. In contrast, the R g values of FITC‐Dex(20k) and FITC‐Dex(40k) were 3.75 nm (5.0 mg/ml) and 6.62 nm (4.0 mg/ml), respectively. These large dextrans probably formed an equivalent complex with ConA on the tube wall. Copyright © 2014 John Wiley & Sons, Ltd.