Table 1.

Summary of the strategies investigated to date to bind lipid molecules on S-layer protein lattices. SLP, S-layer protein; SMCC, succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate; SPDP, N-succinimidyl 3-(2-pyridyldithio)-propionate; TCEP, Tris (2-carboxyethyl) phosphine hydrochloride; NTA, nitrilotriacetic acid.

type	reactive group	cross-linker	targeted group	reference
natural SLP
electrostatic interaction	negatively charges on SLP		zwitterionic or positively charged lipids	[106,107,122]
lectin-type like binding	S-layer-homologous domain on SLP		secondary cell wall polymer coupled to lipids	[123,124]
chemical modification of SLPs
covalent bond	carboxyl groups on SLP	carbodiimide analogues	primary amine group from lipids	[125–129]
covalent bond	primary amino groups on SLP	SMCC analogues	thiol group from lipids	[130]
covalent bond	primary amino groups on SLP	SPDP/TCEP; introduction of thiol group in SLP	maleimide group from lipids	personal communicationa
chemical binding of linker on SLPs
strong ligation	streptavidin chemically coupled to SLP		biotinylated lipids	[115,131]
genetically engineered SLPs
covalent bond	thiol group from introduced cysteine		maleimide group from lipids	[98,132,133]
multiple chelation	multiple histidines (His6-tag) on SLP		nickel(II)-NTA from lipids	[134]
strong ligation	streptavidin fused to SLP		biotinylated lipids	[118]
strong ligation	strep-tag fused to SLP	streptavidin	biotinylated lipids	[99–101]

^aB Schuster et al. 2014, personal communication.