<s>
CheShift-2	O
(	O
pronounced	O
/tʃeʃɪft/	O
)	O
is	O
an	O
application	O
created	O
to	O
compute	O
13Cα	O
and	O
13Cβ	O
protein	O
chemical	O
shifts	O
and	O
to	O
validate	O
protein	O
structures	O
.	O
</s>
<s>
CheShift-2	O
can	O
return	O
a	O
list	O
of	O
theoretical	O
chemical	O
shift	O
values	O
from	O
a	O
PDB	O
file	O
.	O
</s>
<s>
If	O
both	O
13Cα	O
and	O
13Cβ	O
observed	O
chemical	O
shifts	O
are	O
provided	O
CheShift-2	O
will	O
attempt	O
to	O
provide	O
a	O
list	O
of	O
alternative	O
χ1	O
and	O
χ2	O
side-chain	O
torsional	O
angles	O
that	O
will	O
reduce	O
the	O
differences	O
between	O
observed	O
and	O
computed	O
chemical	O
shifts	O
,	O
these	O
values	O
can	O
be	O
used	O
to	O
repair	O
flaws	O
in	O
protein	O
structures	O
.	O
</s>
<s>
CheShift-2	O
can	O
be	O
accessed	O
online	O
at	O
,	O
or	O
via	O
PyMOL	B-Application
.	O
</s>
