How does pH affect secondary structure of proteins?

[TT0]

I understand that pH affect the tertiary structure as it will change the ionic interactions between the COO- and NH3+ groups, however, as the secondary structure is caused by hydrogen bonds, how does pH affect it? Is it because the change in tertiary structure will alter the shape of the protein causing the hydrogen bonds between the NH of the amide and the O of the carbonyl to change?

Thanks!

 

[Borek]

Does the protonation of nitrogen in amide change its readiness to participate in the hydrogen bond?