TABLE 2.

Predicted cleavage by furin, general PCs or trypsin at the XXXR/S motif of CoV S proteins and effects on cleavage and induction of cell-cell fusion by the reproduction of sequence in the second IBV furin site

Group	Species and strain	Summary of cleavage prediction					Reproduction in IBV S			Accession no.
		Position	Sequencea	Score and probabilityb			CLc	Fusiond
				Furin	PCs	Try (%)		Try−	Try+
1	Canine	966	NSKRKYR/SA	0.638	0.858	100	+	++	++	EU856361 and -2
1a	TGEV	956	NSKRKYR/SA	0.638	0.858	100	+	++	++	NC_002306
	Feline 1683	963	NSKRKYR/SA	0.638	0.858	100	+	++	++	X80799
	1146, DF-2	961, 963	NSKRKYG SA				−	−	+	NC_007025, DQ286389
	UCD1	969	PPRVGQR/SA	0.148	0.146	100				AB088222
	NTU2, C1Je	979	PPRIGKR/SA	0.314	0.873	100				DQ160294, DQ848678
	Black	976	PPKIGVR/SA	0.117	0.146	100				EU186072
1b	Human 229E	689	GSRVAGR/SA	0.212	0.208	100	−	+	++	NC_002645
	NL63	870	SSRIAGR/SA	0.168	0.334	100	−	+	++	NC_005831
	PEDVe	891	GRVVQKR/SV	0.611	0.808	100				NC_003436
	Bat 1A	889	PRQHQSR/SA	0.239	0.112	100				NC_010437
	1B	889	PRQRQSR/SA	0.592	0.513	100				NC_010436
	512	885	PANPGAR/SV	0.199	0.242	100				NC_009657
	HKU2	671	SERFESR/SV	0.218	0.267	100				NC_009988
	HKU8	894	PQGGGKR/SV	0.307	0.224	100				NC_010438
2	Equine	913	CNTVSSR/SA	0.147	0.199	100				NC_010327
2a	Bovine	913	CNKVSSR/SA	0.178	0.272	100				NC_003045
	Human HKU1	904	HCGSSSR/SF	0.116	0.238	100				NC_006577
	OC43	911	CSKASSR/SA	0.144	0.169	100				NC_005147
	HEVf	899	CNRASTR/SA	0.162	0.314	100				NC_007732
	MHV A-59, JHM	869, 921	PSAIRGR/SA	0.188	0.392	100	−	++	++	NC_001846, NC_006852
	BHK	876	PRAIRRR/SA	0.416	0.586	89.7				AY497331
	MHV-2	907	MAAQTGR/SA	0.166	0.136	100	−	++	++	AF201929
2b	SARS	797	PLKPTKR/SF	0.261	0.796	100	−	−	++	NC_004718
	Bat Rf1	783	PLKPTKR/SF	0.264	0.796	100	−	−	++	NC_009695
	HKU3, etc.	783, 784	PSKPTKR/SF	0.296	0.896	100				NC_009693, -4, and -6
2c	Bat 133	884	IGGSSYR/SA	0.169	0.226	100				NC_008315
	HKU4-1	886	GSSSSYR/SA	0.264	0.682	100				NC_009019
	HKU5-1	884	TGERKYR/ST	0.507	0.681	100				NC_009020
2d	Bat HKU9-1	809	CGATTYR/SA	0.153	0.123	100				NC_009021
3	IBV M41	690	PSSPRRR/SF	0.304	0.862	75.3	−	−	++	AY851295
	WT	690	PSSRRRR/SV	0.837	0.946	75.3	++	+++	+++	AAY24443
	M2.1	690	PSSPRRR/SV	0.499	0.937	75.3	−	−	++	This study
	M2.5	690	PSSAAAR/SV	0.284	0.074	100	−	+	++	This study
	Turkey	704	LAQNQGR/ST	0.140	0.122	100				NC_010800
	Bulbul	677	TSKAGGR/SA	0.147	0.080	100				NC_011548
	Thrush	707	PNKQGGR/SA	0.131	0.067	100				NC_011549
	CoV SW1	973	SDPRDAR/SA	0.382	0.402	100				NC_010646
	Munia	669	SNKIGEK/SV	0.099	0.093	100				NC_011550

^aThe predicted cleavage site by furin, general PCs, or typsin is indicated by a slash.

^bScores above 0.5 are in boldface.

^cCleavage (CL) at the second furin sites in HuH-7 cells expressing pKT-S(1-789)Fc is indicated by ++ for strong, + for weak, and − for none.

^dCell-cell fusion at neutral pH in Vero cells expressing pKT-S is indicated by +++ for similar to WT, ++ for mild, + for weak, and − for none.

^ePEDV, porcine epidemic diarrhea virus.

^fHEV, porcine hemagglutinating encephalomyelitis virus.