Draw the structure of the predominant form of

$($a$)$ isoleucine at $pH11.($b$)$ proline at $pH2.$

$($c$)$ arginine at $pH7.$

$($d$)$ glutamic acid at $pH7.$

Draw the complete structures of the following peptides:

Marks$)$

$($a$)$ Thr$-$Phe$-$Met $($b$)$

$($b$)$ methionylthreonine

$($c$)$ Glu$-$Cys$-$Gln

$($d$)$ SELVIN