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PDBsum entry 1ht6

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Hydrolase PDB id
1ht6
Jmol
Contents
Protein chain
404 a.a. *
Ligands
EDO ×9
Metals
_CA ×3
Waters ×809
* Residue conservation analysis

References listed in PDB file
Key reference
Title The structure of barley alpha-Amylase isozyme 1 reveals a novel role of domain c in substrate recognition and binding: a pair of sugar tongs.
Authors X.Robert, R.Haser, T.E.Gottschalk, F.Ratajczak, H.Driguez, B.Svensson, N.Aghajari.
Ref. Structure, 2003, 11, 973-984. [DOI no: 10.1016/S0969-2126(03)00151-5]
PubMed id 12906828
Abstract
Though the three-dimensional structures of barley alpha-amylase isozymes AMY1 and AMY2 are very similar, they differ remarkably from each other in their affinity for Ca(2+) and when interacting with substrate analogs. A surface site recognizing maltooligosaccharides, not earlier reported for other alpha-amylases and probably associated with the different activity of AMY1 and AMY2 toward starch granules, has been identified. It is located in the C-terminal part of the enzyme and, thus, highlights a potential role of domain C. In order to scrutinize the possible biological significance of this domain in alpha-amylases, a thorough comparison of their three-dimensional structures was conducted. An additional role for an earlier-identified starch granule binding surface site is proposed, and a new calcium ion is reported.
Figure 4.
Figure 4. Substrate Analogs(A) Chemical structure of the thio-DP4 substrate analog.(B) Chemical structure of acarbose. Rings are labeled as referred to in the text. Rings A and B constitute the acarviosine unit, which is a-1,4 linked to a maltose unit (rings C and D).(C) Schematic representation of interactions in the domain C sugar tongs site, between AMY1 and thio-DP4. The substrate analog is shown in ball and stick in purple. AMY1 ligand side chains, orange. Carbon atoms, black; oxygen, red; nitrogen, blue; sulphur, yellow. Direct hydrogen bonds between the protein and thio-DP4, dashed green lines (lengths in ); hydrophobic contacts, dashed red lines. This figure was generated with the program Ligplot (Wallace et al., 1995).
The above figure is reprinted by permission from Cell Press: Structure (2003, 11, 973-984) copyright 2003.
Secondary reference #1
Title Crystal and molecular structure of barley alpha-Amylase.
Authors A.Kadziola, J.Abe, B.Svensson, R.Haser.
Ref. J Mol Biol, 1994, 239, 104-121.
PubMed id 8196040
Abstract
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