Table 2.

Property groups of amino acids used to derive features.

Groups	Subgroups	AAs	Groups	Subgroups	AAs
R groups	Nonpolar aliphatic	AVLIMG	Hydrophobicity groups	Hydrophobic	VLIMAFPWYCG
	Polar uncharged	SPTCNQ		Hydrophilic basic	KHR
	Positively charged	KHR		Hydrophilic acidic	DE
	Negative	DE		Hydrophilic polar with uncharged side chain	STNQ
	Aromatic	FYW
Exchange groups	E1	KHR	Electronic groups	Electron donor	DEPA
	E2	DENQ		Weak electron donor	VLI
	E3	C		Electron acceptor	KNR
	E4	AGPST		Weak electron acceptor	FYMTQ
	E5	ILMV		Neutral	GHWS
	E6	FYW		Special AA	C
Other groups	Charged	DEKHRVLI	Other groups	Tiny	AG
	Polar	DEKHRNTQSYW		Bulky	FHWYR
	Aromatic	FHWY		Polar-uncharged	NQ
	Small	AGST