<s>
I-TASSER	B-Application
(	O
Iterative	O
Threading	O
ASSEmbly	O
Refinement	O
)	O
is	O
a	O
bioinformatics	O
method	O
for	O
predicting	O
three-dimensional	O
structure	O
model	O
of	O
protein	O
molecules	O
from	O
amino	O
acid	O
sequences	O
.	O
</s>
<s>
The	O
full-length	O
structure	O
models	O
are	O
constructed	O
by	O
reassembling	O
structural	O
fragments	O
from	O
threading	O
templates	O
using	O
replica	B-Algorithm
exchange	I-Algorithm
Monte	B-Algorithm
Carlo	I-Algorithm
simulations	I-Algorithm
.	O
</s>
<s>
I-TASSER	B-Application
is	O
one	O
of	O
the	O
most	O
successful	O
protein	O
structure	O
prediction	O
methods	O
in	O
the	O
community-wide	O
CASP	O
experiments	O
.	O
</s>
<s>
I-TASSER	B-Application
has	O
been	O
extended	O
for	O
structure-based	O
protein	O
function	O
predictions	O
,	O
which	O
provides	O
annotations	O
on	O
ligand	O
binding	O
site	O
,	O
gene	O
ontology	O
and	O
enzyme	O
commission	O
by	O
structurally	O
matching	O
structural	O
models	O
of	O
the	O
target	O
protein	O
to	O
the	O
known	O
proteins	O
in	O
protein	O
function	O
databases	O
.	O
</s>
<s>
A	O
standalone	O
package	O
of	O
I-TASSER	B-Application
is	O
available	O
for	O
download	O
at	O
the	O
.	O
</s>
<s>
I-TASSER	B-Application
(	O
as	O
'	O
Zhang-Server	O
'	O
)	O
has	O
been	O
consistently	O
ranked	O
as	O
the	O
top	O
method	O
in	O
CASP	O
,	O
a	O
community-wide	O
experiment	O
to	O
benchmark	O
the	O
best	O
structure	O
prediction	O
methods	O
in	O
the	O
field	O
of	O
protein	O
folding	O
and	O
protein	O
structure	O
prediction	O
.	O
</s>
<s>
I-TASSER	B-Application
is	O
a	O
template-based	O
method	O
for	O
protein	O
structure	O
and	O
function	O
prediction	O
.	O
</s>
<s>
The	O
I-TASSER	B-Application
server	O
allows	O
users	O
to	O
generate	O
automatically	O
protein	O
structure	O
and	O
function	O
predictions	O
.	O
</s>
<s>
Optional	O
(	O
user	O
can	O
provide	O
optionally	O
restraints	O
and	O
templates	O
to	O
assist	O
I-TASSER	B-Application
modeling	O
)	O
:	O
</s>
<s>
The	O
I-TASSER	B-Application
Suite	O
is	O
a	O
downloadable	O
package	O
of	O
standalone	O
computer	O
programs	O
,	O
developed	O
by	O
the	O
Yang	O
Zhang	O
Lab	O
for	O
protein	O
structure	O
prediction	O
and	O
refinement	O
,	O
and	O
structure-based	O
protein	O
function	O
annotations	O
.	O
</s>
<s>
Through	O
the	O
I-TASSER	B-Application
License	O
,	O
researchers	O
have	O
access	O
to	O
the	O
following	O
standalone	O
programs	O
:	O
</s>
<s>
I-TASSER	B-Application
:	O
A	O
standalone	O
I-TASSER	B-Application
package	O
for	O
protein	O
3D	O
structure	O
prediction	O
and	O
refinement	O
.	O
</s>
<s>
NW-align	O
:	O
A	O
robust	O
program	O
for	O
protein	O
sequence-to-sequence	O
alignments	O
by	O
Needleman-Wunsch	B-Algorithm
algorithm	I-Algorithm
.	O
</s>
<s>
Library	O
:	O
I-TASSER	B-Application
structural	O
and	O
functional	O
template	O
library	O
weekly	O
updated	O
and	O
freely	O
accessible	O
to	O
the	O
I-TASSER	B-Application
users	O
.	O
</s>
<s>
Instruction	O
on	O
how	O
to	O
download	O
and	O
install	O
the	O
I-TASSER	B-Application
Suite	O
can	O
be	O
found	O
at	O
.	O
</s>
