BL/CH 401 Lecture #4 -- Amino Acid Structures

THE FLEXIBLE AMINO ACID

Flexible -- Gly (Glycine) -- in computers Gly = G

{*Figure 11*}

Gly is a unique AA with no chiral center -- but it is prochiral since it has two groups the same (ie H)

on the central carbon -- so it still has sidedness - try making a model of Gly.

Most important since Gly has no side chain it is very flexible and...

can easily twist around its alpha-amino Nitrogen bond to the alpha-Carbon.

Several Gly connected together in a protein can make a swivel joint like structure.

Gly is the opposite of Pro - Gly is flexible while Pro is inflexible.

Finally, Gly makes a transition from the non-polar AAs to the polar AAs.

Gly is neither non-polar or polar ....or maybe it is either non-polar or polar!

©Wilbur H. Campbell, 1995, 1996; wcampbel@mtu.edu

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