Table 1.

Immobilization strategies. Summary of the to date investigated strategies to bind lipid molecules on S-layer protein lattices (modified after [41]).

Type	Reactive Group	Crosslinker	Targeted Group	References
Natural SPLs
Electrostatic interaction	Negative charges on SLP		Zwitterionic or positively charged lipids	[79,80,145]
Lectin-type like binding	S-layer homologous domain on SLP		Secondary cell wall polymer coupled to lipids	[18]
Chemical modi-fication of SLPs
Covalent bond	Carboxyl groups on SLP	Carbodiimide analogues	Primary amine group from lipids	[146,147,168]
Covalent bond	Primary amino groups on SLP	SMCC analogues	Thiol group from lipids	[148]
Covalent bond	Primary amino groups on SLP	SPDP/TCEP; insertion of thiol group in SLP	Maleimide group from lipids	Schuster et al. in preparation
Chemical binding of linker on SLPs
Strong ligation	Streptavidin chemically coupled to SLP		Biotinylated lipids	[149,150]
Genetically engineered SLPs
Covalent bond	Thiol-group from introduced cysteine		Maleimide group from lipids	[151,152,153]
Multiple chelation	Multiple histidines (His6-tag) on SLP		Nickel(II)-NTA from lipids	[154]
Strong ligation	Streptavidin fused to SLP		Biotinylated lipids	[89]
Strong ligation	Strep-tag fused to SLP	Streptavidin	Biotinylated lipids	[72,73,155]

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.