From Proteopedia
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| - | [[Image:1iop.gif|left|200px]] | + | {{Seed}} |
| | + | [[Image:1iop.png|left|200px]] |
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| | {{STRUCTURE_1iop| PDB=1iop | SCENE= }} | | {{STRUCTURE_1iop| PDB=1iop | SCENE= }} |
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| - | '''INCORPORATION OF A HEMIN WITH THE SHORTEST ACID SIDE-CHAINS INTO MYOGLOBIN'''
| + | ===INCORPORATION OF A HEMIN WITH THE SHORTEST ACID SIDE-CHAINS INTO MYOGLOBIN=== |
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| - | ==Overview==
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| - | Myoglobin was reconstituted with 6,7-dicarboxy-1,2,3,4,5, 8-hexamethylheme, a compact synthetic heme with the shortest acid side chains, to pursue the structural and functional consequences after intensive disruption of the heme propionate-apoglobin linkages in the native protein. The electron-withdrawing carboxylate groups directly attached to the porphyrin ring lowered the oxygen affinity by 3-fold as compared with native myoglobin. Autoxidation of the oxy derivative to the ferric protein proceeded with 1.6 x 10(-)2 min-1 at pH 7.0 and 30 degrees C. The crystallographic structure of the cyanomet myoglobin with 1.9 A resolution shows that the heme adopts a unique orientation in the protein pocket to extend the two carboxylates toward solvent sphere. The native globin fold is conserved, and the conformations of globin side chains are almost intact except for those located nearby the heme 6,7-carboxylates. The 7-carboxylate only weakly interacts with Ser92 and His97 through two mediating water molecules. The 6-carboxylate, on the other hand, forms a novel salt bridge with Arg45 owing to conformational flexibility of the guanidinium side chain. The proton NMR shows that the small heme does not fluctuate about the iron-histidine bond even at 55 degreesC, suggesting that the salt bridge between Arg45 and heme 6-carboxylate is of critical importance to recognize and fix the heme in myoglobin.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_9548931}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 9548931 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_9548931}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Globin fold]] | | [[Category: Globin fold]] |
| | [[Category: Oxygen transport]] | | [[Category: Oxygen transport]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 20:13:50 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 13:42:39 2008'' |
Revision as of 10:42, 1 July 2008
Template:STRUCTURE 1iop
INCORPORATION OF A HEMIN WITH THE SHORTEST ACID SIDE-CHAINS INTO MYOGLOBIN
Template:ABSTRACT PUBMED 9548931
About this Structure
1IOP is a Single protein structure of sequence from Physeter catodon. Full crystallographic information is available from OCA.
Reference
Structure and function of 6,7-dicarboxyheme-substituted myoglobin., Neya S, Funasaki N, Igarashi N, Ikezaki A, Sato T, Imai K, Tanaka N, Biochemistry. 1998 Apr 21;37(16):5487-93. PMID:9548931
Page seeded by OCA on Tue Jul 1 13:42:39 2008
