1dly
From Proteopedia
(New page: 200px<br /> <applet load="1dly" size="450" color="white" frame="true" align="right" spinBox="true" caption="1dly, resolution 1.8Å" /> '''X-RAY CRYSTAL STRUCT...) |
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| - | [[Image:1dly.gif|left|200px]]<br /> | + | [[Image:1dly.gif|left|200px]]<br /><applet load="1dly" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1dly" size=" | + | |
caption="1dly, resolution 1.8Å" /> | caption="1dly, resolution 1.8Å" /> | ||
'''X-RAY CRYSTAL STRUCTURE OF HEMOGLOBIN FROM THE GREEN UNICELLULAR ALGA CHLAMYDOMONAS EUGAMETOS'''<br /> | '''X-RAY CRYSTAL STRUCTURE OF HEMOGLOBIN FROM THE GREEN UNICELLULAR ALGA CHLAMYDOMONAS EUGAMETOS'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Small hemoproteins displaying amino acid sequences 20-40 residues shorter | + | Small hemoproteins displaying amino acid sequences 20-40 residues shorter than (non-)vertebrate hemoglobins (Hbs) have recently been identified in several pathogenic and non-pathogenic unicellular organisms, and named 'truncated hemoglobins' (trHbs). They have been proposed to be involved not only in oxygen transport but also in other biological functions, such as protection against reactive nitrogen species, photosynthesis or to act as terminal oxidases. Crystal structures of trHbs from the ciliated protozoan Paramecium caudatum and the green unicellular alga Chlamydomonas eugametos show that the tertiary structure of both proteins is based on a 'two-over-two' alpha-helical sandwich, reflecting an unprecedented editing of the classical 'three-over-three' alpha-helical globin fold. Based on specific Gly-Gly motifs the tertiary structure accommodates the deletion of the N-terminal A-helix and replacement of the crucial heme-binding F-helix with an extended polypeptide loop. Additionally, concerted structural modifications allow burying of the heme group and define the distal site, which hosts a TyrB10, GlnE7 residue pair. A set of structural and amino acid sequence consensus rules for stabilizing the fold and the bound heme in the trHbs homology subfamily is deduced. |
==About this Structure== | ==About this Structure== | ||
| - | 1DLY is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Chlamydomonas_eugametos Chlamydomonas eugametos] with CYN, SO4, HEM and EDO as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1DLY is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Chlamydomonas_eugametos Chlamydomonas eugametos] with <scene name='pdbligand=CYN:'>CYN</scene>, <scene name='pdbligand=SO4:'>SO4</scene>, <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=EDO:'>EDO</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DLY OCA]. |
==Reference== | ==Reference== | ||
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[[Category: globin fold truncated hemoglobin]] | [[Category: globin fold truncated hemoglobin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:18:06 2008'' |
Revision as of 10:18, 21 February 2008
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X-RAY CRYSTAL STRUCTURE OF HEMOGLOBIN FROM THE GREEN UNICELLULAR ALGA CHLAMYDOMONAS EUGAMETOS
Overview
Small hemoproteins displaying amino acid sequences 20-40 residues shorter than (non-)vertebrate hemoglobins (Hbs) have recently been identified in several pathogenic and non-pathogenic unicellular organisms, and named 'truncated hemoglobins' (trHbs). They have been proposed to be involved not only in oxygen transport but also in other biological functions, such as protection against reactive nitrogen species, photosynthesis or to act as terminal oxidases. Crystal structures of trHbs from the ciliated protozoan Paramecium caudatum and the green unicellular alga Chlamydomonas eugametos show that the tertiary structure of both proteins is based on a 'two-over-two' alpha-helical sandwich, reflecting an unprecedented editing of the classical 'three-over-three' alpha-helical globin fold. Based on specific Gly-Gly motifs the tertiary structure accommodates the deletion of the N-terminal A-helix and replacement of the crucial heme-binding F-helix with an extended polypeptide loop. Additionally, concerted structural modifications allow burying of the heme group and define the distal site, which hosts a TyrB10, GlnE7 residue pair. A set of structural and amino acid sequence consensus rules for stabilizing the fold and the bound heme in the trHbs homology subfamily is deduced.
About this Structure
1DLY is a Single protein structure of sequence from Chlamydomonas eugametos with , , and as ligands. Full crystallographic information is available from OCA.
Reference
A novel two-over-two alpha-helical sandwich fold is characteristic of the truncated hemoglobin family., Pesce A, Couture M, Dewilde S, Guertin M, Yamauchi K, Ascenzi P, Moens L, Bolognesi M, EMBO J. 2000 Jun 1;19(11):2424-34. PMID:10835341
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