Glycine rich loops

[biology_06er]

Hi there,

Was going through a past test questions and need some help with the following question:

The glycine rich loop of protein kinases contains highly conserved glycine residues. Why are they conserved?

possible info??
Glycine is flexible therefore allows loop to open up to phosphorylate proteins..important protein thus remains more or less the same sequence in many species..glycine rich loop imp. in catalytic site

Any other info much appreciated

cheers,
b_06er