Table 1.

ITC analysis of hPar-4 peptide interactions with mSPSB proteins

Ligands	Proteins	Kda
hPar-4(59–77) GTPAAAAANELNNNLPGGA	mSPSB2(12–224)	4.6 ± 0.1 μM
	mSPSB4ΔSB	189 ± 1 nM
	mSPSB2 + elonginBC	4.3 ± 0.6 μM
	mSPSB4 + elonginBC	214 ± 36 nM
	mSPSB2(12–224)[Y120A]	nmb
	mSPSB2(12–224)[123–5]	nm
	mSPSB2(12–224)[126–8]	nm
	mSPSB2(12–224)[T198A]	3.0 ± 0.2 μM
	mSPSB2(12–224)[V206A]	nm
[N72A]hPar-4(59–77) GTPAAAAANELNNALPGGA	mSPSB2(12–224)	nm
	mSPSB4 + elonginBC	nm
hPar-4(64–77) AAANELNNNLPGGA	mSPSB2(12–224)	3.2 ± 0.002 μM
	mSPSB4ΔSB	213 ± 7 nM
	mSPSB1ΔSB	210 ± 19 nM
[N70A]hPar-4(64–77) AAANELANNLPGGA	mSPSB2(12–224)	nm
	mSPSB4ΔSB	nm
	mSPSB1ΔSB	nm
[N71A]hPar-4(64–77) AAANELNANLPGGA	mSPSB2(12–224)	nm
	mSPSB4ΔSB	nm
	mSPSB1ΔSB	nm
[E68D,L69I]hPar-4(64–77) AAANDINNNLPGGA	mSPSB2(12–224)	106 ± 30 nM
	mSPSB4ΔSB	33 ± 23 nM
	mSPSB1ΔSB	40 ± 5 nM
[E68D]hPar-4(64–77) AAANDLNNNLPGGA	mSPSB2(12–224)	208 ± 13 nM
	mSPSB4ΔSB	47 ± 22 nM
[L69I]hPar-4(64–77) AAANEINNNLPGGA	mSPSB2(12–224)	1.6 ± 0.4 μM
	mSPSB4ΔSB	55 ± 8 nM
[A66D]hPar-4(59–77) GTPAAAADNELNNNLPGGA	mSPSB2(12–224)	4.0 ± 0.9 μM
	mSPSB4ΔSB	255 ± 5 nM

^aK_d value deviations are shown as the standard error of the mean.

^bnm, not measurable because  K_d > 50 μM.