 |
PDBsum entry 1af4
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Serine protease
|
PDB id
|
|
|
|
1af4
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
The crystal structure of subtilisin carlsberg in anhydrous dioxane and its comparison with those in water and acetonitrile.
|
|
|
Authors
|
|
J.L.Schmitke,
L.J.Stern,
A.M.Klibanov.
|
|
|
Ref.
|
|
Proc Natl Acad Sci U S A, 1997,
94,
4250-4255.
[DOI no: ]
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
The x-ray crystal structure of the serine protease subtilisin Carlsberg in
anhydrous dioxane has been determined to 2.6-A resolution. The enzyme structure
is found to be nearly indistinguishable from the structures previously
determined in water and acetonitrile. Small changes in the side-chain
conformations between the dioxane and water structures are of the same magnitude
as those observed between two structures in different aqueous systems. Seven
enzyme-bound dioxane molecules have been detected, each potentially forming at
least one hydrogen bond with a subtilisin hydrogen-bond donor or bound water.
Two of the bound dioxane molecules are in the active-site region, one in the P2
and another bridging the P1' and P3' pockets. The other five dioxane molecules
are located on the surface of subtilisin at interprotein crystal contacts. The
locations of the bound solvent in the dioxane structure are distinct from those
in the structures in acetonitrile and in water.
|
|
|
|
|
|
|
|
Figure 3.
Fig. 3. (A) Refined crystallographic B factors (residue
average) of subtilisin Carlsberg in dioxane (solid line), water
(dashed line), and acetonitrile (dotted line). The difference in
the exposed^ surface areas of subtilisin between dioxane and
water (B) and^ between acetonitrile and water (C). As in Fig. 2,
Ser-159 and^ Gly-160 are left out in A and B.
|
|
Figure 4.
Fig. 4. Active site of subtilisin Carlsberg in anhydrous
dioxane compared with that in water (A) and acetonitrile (B).
The catalytic^ triad, Asn-155 of the oxyanion hole (OH), and
solvent molecules in the dioxane structure are shown as
balls-and-sticks with carbon, oxygen, and nitrogen shown in
white, light-gray, and black, respectively. The water molecules
in the aqueous and acetonitrile structures are depicted as
dark-gray balls in A and B. The acetonitrile molecules in that
structure (B) are also shown as linear balls-and-sticks. The
surface of the protein [Connolly algorithm (20)] in the^
active-site region in the dioxane structure is portrayed by
black dots.
|
|
|
|
|
|
|
|
|
|
