4.2.2. Not mirror antisymmetry



The side chains of amino acids having not mirror antisymmetry, are located on the dodecahedron on opposite sides of the plane II: behind the plane II (background in the circles is painted in pale pink), and prior to that plane (dark pink background). For brevity we shall speak:  behind a plane and prior a plane, the name referring to the plane II. They are connected among themselves by transition which we have designated by the letter beta (b). In this case the side chains in pairs usually have similar size but different physical properties.







































































At the very top on the right the side chains of serine (Ser - behind the plane) and cysteine ​​(Cys - in front of the plane) are sitiuated. The size of their side chains is close, however a serine has neutral C-OH group, and cysteine ​​- slightly acidic C-SH-group.


At the left pairs of threonine (Thr – behind the  plane) and methionine (Met - in front of the plane) are situated. Their properties repeat right pair.


Below on the right pairs of aspartic acid (Asp - behind the plane) and asparagine (Asn - in front of the plane) settle down. The length of the side chains is identical, but the polar group О=СОН is changed to nonpolar O=C–NH2 when passing through the plane.

At the left there is a pair of glutamic acid (Glu - behind the plane) and glutamine (Gln - in front of the plane). They are also similar in length. In this pair similar changes in the side chains are observed.


Even lower on the right a pair of valine (Val - - behind the plane) and arginine (Arg - in front of the plane) is situated, in which we we observe a transition from a nonpolar to a polar group (N=CNH). On the left a pair of isoleucine (Ile - - behind the plane) and lysin (Lys - in front of the plane) settles down, in which change of properties similarly.


At the very bottom on the right there is a pair of cyclic amino acid phenylalanine (Phe – behind the plane) and histidine (His - in front of the plane). At transition through the plane a six-membered ring is replaced by a five-membered, although their size varies insignificantly.


Similar changes are observed for the left pair - the tyrosine (Tyr - - behind the plane) and tryptophan (Trp - in front of the plane).

























































































Thus, at transition through the plane II side chains with insignificant differences in side chain essentially change their physical properties.


For the further acquaintance with the antisymmetry of the amino acids which come to light by means of our model, pass in sections 4.2.1., 4.2.3., 4.2.4. or return to the  section 4.


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