Table 2. Important functional motifs in non-bat influenza A internal proteins are largely conserved in bat influenza proteins.

Protein	Position(s)	Non-bat viruses	A/bat/Guat/09	A/bat/Peru/10	Comment
PB2	2–4, 6–7	ERI, EL	DRI, EL †		Direct contact with PB1
	627	E or K	S		E associated with avian viruses, K with mammalian viruses
	701	D or N	N		N associated with adaptation to mice
	737–739	RKR			Minor nuclear localization signal
	752–755	KRIR			Major nuclear localization signal
PB1	5–10	PTLLFL	PMLIFL		Binding to PA
	444–446	SDD			Catalytic activity (equivalent to GDD of positive strand viruses)
PA	80, 108, 119	E, D, E			Endonuclease catalytic domain
	102, 510	K, H			Cap-snatching activity
	408, 412, 620, 621, 623, 670, 673, 706	Q, N, P, I, E, Q, R, W			PB1 binding
NP	3–13	TxGTKRSYxxM	TxGLKRTFxxM	GxGTKRTFxxM	Nuclear localization signal
M1	101–105	RKLKR	KKLKK		Nuclear localization signal
M2	31	S or N	N		N31 is associated with adamantane resistance
NS1	35–41	DRLRR			Nuclear localization signal
	103	F	V		CPSF30 binding/stabilization
	106	M	Q
	138–147	FDRLETLILL	FGKLERLVLA	FGKVERLVLA	Nuclear export signal
	227–230	ESEV or absent	absent		PDZ ligand binding domain
NS2	12–21	ILxRMSKMQL			Nuclear export signal

^†Letters written as subscripts denote amino acid substitutions in bat viruses compared to the consensus non-bat amino acid sequence.