write the one letter code for the oligopeptide thr $-$ his $-$ ile $-$ ser $-$ ile $-$ser $-$ glu $-$ ala $-$ ser $-$ tyr and calculate the total charge on it at pH $9.7$side chain pkA values $4.0,$Glu $5.0,$His $6.5,$Cys $8.5,$Ty$r,10.0,$Lys $10.2,$Arg $12.5$a $-$ amino group $,9.6,$a$-$carboxyl group $2.4,$ N terminal amino group $9.5,$ C $-$terminal carboxyl group $2.5$