TABLE 3.

Cleavage efficiency at the p28 and p65 sites, using polypeptides of increasing length as sources of PLP-1

Enzymea	Length (amino acids)b	Mass (kDa)c	Cleavage efficiency (%)d
			pSPN1S1	pSPΔMscN1S1
SpeI	294	31.9	0	1
BstXI	448	49.2	18	16
NsiI	638	69.3	33	29
ClaI	904	99.2	48	48
AgeI	1,161	128.0	100	100

^aTo synthesize PLP-1-containing polypeptides, plasmid pCITE P₁P_2a (Fig. 1B) was linearized with the enzymes listed, followed by in vitro transcription-translation in the presence of 0.1 mM unlabeled methionine. 

^bLengths of polypeptides synthesized by using the truncated plasmid templates. 

^cPredicted molecular mass of corresponding viral polypeptides. 

^dSubstrates were synthesized in similar reactions using [³⁵S]methionine and either pSPN₁S₁ or pSPΔMscN₁S₁ as the template. Cleavage efficiency was calculated as described in Materials and Methods; the cleavage efficiency with the longest enzyme polypeptide was arbitrarily set to 100%.