1rwf
From Proteopedia
(New page: 200px<br /><applet load="1rwf" size="450" color="white" frame="true" align="right" spinBox="true" caption="1rwf, resolution 1.45Å" /> '''Crystal structure of...) |
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| - | [[Image:1rwf.jpg|left|200px]]<br /><applet load="1rwf" size=" | + | [[Image:1rwf.jpg|left|200px]]<br /><applet load="1rwf" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1rwf, resolution 1.45Å" /> | caption="1rwf, resolution 1.45Å" /> | ||
'''Crystal structure of Arthrobacter aurescens chondroitin AC lyase in complex with chondroitin tetrasaccharide'''<br /> | '''Crystal structure of Arthrobacter aurescens chondroitin AC lyase in complex with chondroitin tetrasaccharide'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Chondroitin lyases (EC 4.2.2.4 and EC 4.2.2.5) are | + | Chondroitin lyases (EC 4.2.2.4 and EC 4.2.2.5) are glycosaminoglycan-degrading enzymes that act as eliminases. Chondroitin lyase AC from Arthrobacter aurescens (ArthroAC) is known to act on chondroitin 4-sulfate and chondroitin 6-sulfate but not on dermatan sulfate. Like other chondroitin AC lyases, it is capable of cleaving hyaluronan. We have determined the three-dimensional crystal structure of ArthroAC in its native form as well as in complex with its substrates (chondroitin 4-sulfate tetrasaccharide, CS(tetra) and hyaluronan tetrasaccharide) at resolution varying from 1.25 A to 1.9A. The primary sequence of ArthroAC has not been previously determined but it was possible to determine the amino acid sequence of this enzyme from the high-resolution electron density maps and to confirm it by mass spectrometry. The enzyme-substrate complexes were obtained by soaking the substrate into the crystals for varying lengths of time (30 seconds to ten hours) and flash-cooling the crystals. The electron density map for crystals soaked in the substrate for as short as 30 seconds showed the substrate clearly and indicated that the ring of central glucuronic acid assumes a distorted boat conformation. This structure strongly supports the lytic mechanism where Tyr242 acts as a general base that abstracts the proton from the C5 position of glucuronic acid while Asn183 and His233 neutralize the charge on the glucuronate acidic group. Comparison of this structure with that of chondroitinase AC from Flavobacterium heparinum (FlavoAC) provides an explanation for the exolytic and endolytic mode of action of ArthroAC and FlavoAC, respectively. |
==About this Structure== | ==About this Structure== | ||
| - | 1RWF is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Arthrobacter_aurescens Arthrobacter aurescens] with NA and PO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1RWF is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Arthrobacter_aurescens Arthrobacter aurescens] with <scene name='pdbligand=NA:'>NA</scene> and <scene name='pdbligand=PO4:'>PO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1RWF OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Arthrobacter aurescens]] | [[Category: Arthrobacter aurescens]] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: Bell, A | + | [[Category: Bell, A W.]] |
[[Category: Cygler, M.]] | [[Category: Cygler, M.]] | ||
[[Category: Kyogashima, M.]] | [[Category: Kyogashima, M.]] | ||
[[Category: Li, Y.]] | [[Category: Li, Y.]] | ||
| - | [[Category: Lunin, V | + | [[Category: Lunin, V V.]] |
[[Category: Miyazono, H.]] | [[Category: Miyazono, H.]] | ||
[[Category: NA]] | [[Category: NA]] | ||
| Line 25: | Line 25: | ||
[[Category: chondroitinase]] | [[Category: chondroitinase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:55:15 2008'' |
Revision as of 12:55, 21 February 2008
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Crystal structure of Arthrobacter aurescens chondroitin AC lyase in complex with chondroitin tetrasaccharide
Overview
Chondroitin lyases (EC 4.2.2.4 and EC 4.2.2.5) are glycosaminoglycan-degrading enzymes that act as eliminases. Chondroitin lyase AC from Arthrobacter aurescens (ArthroAC) is known to act on chondroitin 4-sulfate and chondroitin 6-sulfate but not on dermatan sulfate. Like other chondroitin AC lyases, it is capable of cleaving hyaluronan. We have determined the three-dimensional crystal structure of ArthroAC in its native form as well as in complex with its substrates (chondroitin 4-sulfate tetrasaccharide, CS(tetra) and hyaluronan tetrasaccharide) at resolution varying from 1.25 A to 1.9A. The primary sequence of ArthroAC has not been previously determined but it was possible to determine the amino acid sequence of this enzyme from the high-resolution electron density maps and to confirm it by mass spectrometry. The enzyme-substrate complexes were obtained by soaking the substrate into the crystals for varying lengths of time (30 seconds to ten hours) and flash-cooling the crystals. The electron density map for crystals soaked in the substrate for as short as 30 seconds showed the substrate clearly and indicated that the ring of central glucuronic acid assumes a distorted boat conformation. This structure strongly supports the lytic mechanism where Tyr242 acts as a general base that abstracts the proton from the C5 position of glucuronic acid while Asn183 and His233 neutralize the charge on the glucuronate acidic group. Comparison of this structure with that of chondroitinase AC from Flavobacterium heparinum (FlavoAC) provides an explanation for the exolytic and endolytic mode of action of ArthroAC and FlavoAC, respectively.
About this Structure
1RWF is a Protein complex structure of sequences from Arthrobacter aurescens with and as ligands. Full crystallographic information is available from OCA.
Reference
High-resolution crystal structure of Arthrobacter aurescens chondroitin AC lyase: an enzyme-substrate complex defines the catalytic mechanism., Lunin VV, Li Y, Linhardt RJ, Miyazono H, Kyogashima M, Kaneko T, Bell AW, Cygler M, J Mol Biol. 2004 Mar 19;337(2):367-86. PMID:15003453
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