1O9J
The X-ray crystal structure of eta-crystallin
Summary for 1O9J
| Entry DOI | 10.2210/pdb1o9j/pdb |
| Descriptor | ALDEHYDE DEHYDROGENASE, CYTOSOLIC 1, NICOTINAMIDE-ADENINE-DINUCLEOTIDE, 2,3-DIHYDROXY-1,4-DITHIOBUTANE, ... (5 entities in total) |
| Functional Keywords | aldh, eye-lens protein, eta-crystallin, oxidoreductase |
| Biological source | ELEPHANTULUS EDWARDII (CAPE LONG-EARED ELEPHANT SHREW) |
| Cellular location | Cytoplasm (By similarity): Q28399 |
| Total number of polymer chains | 4 |
| Total formula weight | 221359.59 |
| Authors | Purkiss, A.G.,Van Montfort, R.,Wistow, G.,Slingsby, C. (deposition date: 2002-12-15, release date: 2003-04-17, Last modification date: 2023-12-13) |
| Primary citation | Bateman, O.A.,Purkiss, A.G.,Van Montfort, R.,Slingsby, C.,Graham, C.,Wistow, G. Crystal Structure of Eta-Crystallin: Adaptation of a Class 1 Aldehyde Dehydrogenase for a New Role in the Eye Lens Biochemistry, 42:4349-, 2003 Cited by PubMed Abstract: Eta-crystallin is a retinal dehydrogenase that has acquired a role as a structural protein in the eye lens of elephant shrews, members of an ancient order of mammals. While it retains some activity toward retinal, which is oxidized to retinoic acid, the protein has acquired a number of specific sequence changes that have presumably been selected to enhance the lens role. The crystal structure of eta-crystallin, in common with class 1 and 2 ALDHs, is a dimer of dimers. It has a better-defined NAD binding site than those of related mammalian ALDH1 enzymes with the cofactor bound in the "hydride transfer" position in all four monomers with small differences about the dimer dyads. Although the active site is well conserved, the substrate-binding site is larger in eta-crystallin, and there are some mutations to the substrate access tunnel that might affect binding or release of substrate and product. It is possible that eta-crystallin has lost flexibility to improve its role in the lens. Enhanced binding of cofactor could enable it to act as a UV/blue light filter in the lens, improving visual acuity. The structure not only gives a view of a "natural mutant" of ALDH1 illustrating the adaptive conflict that can arise in multifunctional proteins, but also provides a well-ordered NAD binding site structure for this class of enzymes with important roles in development and health. PubMed: 12693930DOI: 10.1021/BI027367W PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.4 Å) |
Structure validation
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