(Solved): please help  Match the figures of the protonation states of histidine shown below to the \( \ma ...

Match the figures of the protonation states of histidine shown below to the \( \mathrm{pH} \) at which this protonation state would be dominant. The \( \mathrm{pKa} \) values for histidine are \( \mathrm{pK} /(\alpha-\mathrm{COOH})=1.80, \mathrm{pK} \mathrm{R} \) (side chain) \( =6.04 \), and \( \mathrm{pK}_{2}\left(\mathrm{NH}_{3}{ }^{+}\right)= \) \( 9.33 . \) How many hydrogen bond donors on the histidine side chain are available at \( \mathrm{pH} 8.0 \) ?