1hdf
From Proteopedia
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==Overview== | ==Overview== | ||
| - | BACKGROUND: The betagamma-crystallins belong to a superfamily of, two-domain proteins found in vertebrate eye lenses, with distant relatives, occurring in microorganisms. It has been considered that an eukaryotic, stress protein, spherulin 3a, from the slime mold Physarum polycephalum, shares a common one-domain ancestor with crystallins, similar to the, one-domain 3-D structure determined by NMR. RESULTS: The X-ray structure, of spherulin 3a shows it to be a tight homodimer, which is consistent with, ultracentrifugation studies. The (two-motif) domain fold contains a pair, of calcium binding sites very similar to those found in a two-domain, prokaryotic betagamma-crystallin fold family member, Protein S. Domain, pairing in the spherulin 3a dimer is two-fold symmetric, but quite, .. | + | BACKGROUND: The betagamma-crystallins belong to a superfamily of, two-domain proteins found in vertebrate eye lenses, with distant relatives, occurring in microorganisms. It has been considered that an eukaryotic, stress protein, spherulin 3a, from the slime mold Physarum polycephalum, shares a common one-domain ancestor with crystallins, similar to the, one-domain 3-D structure determined by NMR. RESULTS: The X-ray structure, of spherulin 3a shows it to be a tight homodimer, which is consistent with, ultracentrifugation studies. The (two-motif) domain fold contains a pair, of calcium binding sites very similar to those found in a two-domain, prokaryotic betagamma-crystallin fold family member, Protein S. Domain, pairing in the spherulin 3a dimer is two-fold symmetric, but quite, different in character from the pseudo-two-fold pairing of domains in, betagamma-crystallins. There is no evidence that the spherulin 3a single, domain can fold independently of its partner domain, a feature that may be, related to the absence of a tyrosine corner. CONCLUSION: Although it is, accepted that the vertebrate two-domain betagamma-crystallins evolved from, a common one-domain ancestor, the mycetezoan single-domain spherulin 3a, with its unique mode of domain pairing, is likely to be an evolutionary, offshoot, perhaps from as far back as the one-motif ancestral stage. The, spherulin 3a protomer stability appears to be dependent on domain pairing., Spherulin-like domain sequences that are found within bacterial proteins, associated with virulence are likely to bind calcium. |
==About this Structure== | ==About this Structure== | ||
| - | 1HDF is a | + | 1HDF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Physarum_polycephalum Physarum polycephalum] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Sites: CA1, CA2, CA3 and CA4. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1HDF OCA]. |
==Reference== | ==Reference== | ||
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[[Category: tyrosine corner]] | [[Category: tyrosine corner]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 15:10:24 2007'' |
Revision as of 13:05, 5 November 2007
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EVOLUTION OF THE EYE LENS BETA-GAMMA-CRYSTALLIN DOMAIN FOLD
Overview
BACKGROUND: The betagamma-crystallins belong to a superfamily of, two-domain proteins found in vertebrate eye lenses, with distant relatives, occurring in microorganisms. It has been considered that an eukaryotic, stress protein, spherulin 3a, from the slime mold Physarum polycephalum, shares a common one-domain ancestor with crystallins, similar to the, one-domain 3-D structure determined by NMR. RESULTS: The X-ray structure, of spherulin 3a shows it to be a tight homodimer, which is consistent with, ultracentrifugation studies. The (two-motif) domain fold contains a pair, of calcium binding sites very similar to those found in a two-domain, prokaryotic betagamma-crystallin fold family member, Protein S. Domain, pairing in the spherulin 3a dimer is two-fold symmetric, but quite, different in character from the pseudo-two-fold pairing of domains in, betagamma-crystallins. There is no evidence that the spherulin 3a single, domain can fold independently of its partner domain, a feature that may be, related to the absence of a tyrosine corner. CONCLUSION: Although it is, accepted that the vertebrate two-domain betagamma-crystallins evolved from, a common one-domain ancestor, the mycetezoan single-domain spherulin 3a, with its unique mode of domain pairing, is likely to be an evolutionary, offshoot, perhaps from as far back as the one-motif ancestral stage. The, spherulin 3a protomer stability appears to be dependent on domain pairing., Spherulin-like domain sequences that are found within bacterial proteins, associated with virulence are likely to bind calcium.
About this Structure
1HDF is a Single protein structure of sequence from Physarum polycephalum with CA as ligand. Structure known Active Sites: CA1, CA2, CA3 and CA4. Full crystallographic information is available from OCA.
Reference
Crystal structure of the calcium-loaded spherulin 3a dimer sheds light on the evolution of the eye lens betagamma-crystallin domain fold., Clout NJ, Kretschmar M, Jaenicke R, Slingsby C, Structure. 2001 Feb 7;9(2):115-24. PMID:11250196
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