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1egn

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Revision as of 09:25, 6 November 2019

CELLOBIOHYDROLASE CEL7A (E223S, A224H, L225V, T226A, D262G) MUTANT

Structural highlights

1egn is a 1 chain structure with sequence from Atcc 13631. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:	,
NonStd Res:
Related:	4cel, 7cel, 1ek7, 1dy4, 1i5m
Activity:	Cellulose 1,4-beta-cellobiosidase (non-reducing end), with EC number 3.2.1.91
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[GUX1_HYPJE] The biological conversion of cellulose to glucose generally requires three types of hydrolytic enzymes: (1) Endoglucanases which cut internal beta-1,4-glucosidic bonds; (2) Exocellobiohydrolases that cut the dissaccharide cellobiose from the non-reducing end of the cellulose polymer chain; (3) Beta-1,4-glucosidases which hydrolyze the cellobiose and other short cello-oligosaccharides to glucose.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

The crystal structures of Family 7 glycohydrolases suggest that a histidine residue near the acid/base catalyst could account for the higher pH optimum of the Humicola insolens endoglucanase Cel7B, than the corresponding Trichoderma reesei enzymes. Modelling studies indicated that introduction of histidine at the homologous position in T. reesei Cel7A (Ala(224)) required additional changes to accommodate the bulkier histidine side chain. X-ray crystallography of the catalytic domain of the E223S/A224H/L225V/T226A/D262G mutant reveals that major differences from the wild-type are confined to the mutations themselves. The introduced histidine residue is in plane with its counterpart in H. insolens Cel7B, but is 1.0 A (=0.1 nm) closer to the acid/base Glu(217) residue, with a 3.1 A contact between N(epsilon2) and O(epsilon1). The pH variation of k(cat)/K(m) for 3,4-dinitrophenyl lactoside hydrolysis was accurately bell-shaped for both wild-type and mutant, with pK(1) shifting from 2.22+/-0.03 in the wild-type to 3.19+/-0.03 in the mutant, and pK(2) shifting from 5.99+/-0.02 to 6.78+/-0.02. With this poor substrate, the ionizations probably represent those of the free enzyme. The relative k(cat) for 2-chloro-4-nitrophenyl lactoside showed similar behaviour. The shift in the mutant pH optimum was associated with lower k(cat)/K(m) values for both lactosides and cellobiosides, and a marginally lower stability. However, k(cat) values for cellobiosides are higher for the mutant. This we attribute to reduced non-productive binding in the +1 and +2 subsites; inhibition by cellobiose is certainly relieved in the mutant. The weaker binding of cellobiose is due to the loss of two water-mediated hydrogen bonds.

Engineering of a glycosidase Family 7 cellobiohydrolase to more alkaline pH optimum: the pH behaviour of Trichoderma reesei Cel7A and its E223S/ A224H/L225V/T226A/D262G mutant.,Becker D, Braet C, Brumer H 3rd, Claeyssens M, Divne C, Fagerstrom BR, Harris M, Jones TA, Kleywegt GJ, Koivula A, Mahdi S, Piens K, Sinnott ML, Stahlberg J, Teeri TT, Underwood M, Wohlfahrt G Biochem J. 2001 May 15;356(Pt 1):19-30. PMID:11336632^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Becker D, Braet C, Brumer H 3rd, Claeyssens M, Divne C, Fagerstrom BR, Harris M, Jones TA, Kleywegt GJ, Koivula A, Mahdi S, Piens K, Sinnott ML, Stahlberg J, Teeri TT, Underwood M, Wohlfahrt G. Engineering of a glycosidase Family 7 cellobiohydrolase to more alkaline pH optimum: the pH behaviour of Trichoderma reesei Cel7A and its E223S/ A224H/L225V/T226A/D262G mutant. Biochem J. 2001 May 15;356(Pt 1):19-30. PMID:11336632

1 Structural highlights
2 Function
3 Evolutionary Conservation
4 Publication Abstract from PubMed
5 See Also
6 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1egn"

@@ Line 1: / Line 1: @@
 ==CELLOBIOHYDROLASE CEL7A (E223S, A224H, L225V, T226A, D262G) MUTANT==
-<StructureSection load='1egn' size='340' side='right' caption='[[1egn]], [[Resolution|resolution]] 1.60&Aring;' scene=''>
+<StructureSection load='1egn' size='340' side='right'caption='[[1egn]], [[Resolution|resolution]] 1.60&Aring;' scene=''>
 == Structural highlights ==
 <table><tr><td colspan='2'>[[1egn]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Atcc_13631 Atcc 13631]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EGN OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1EGN FirstGlance]. <br>
@@ Line 31: / Line 31: @@
 </div>
 <div class="pdbe-citations 1egn" style="background-color:#fffaf0;"></div>
+==See Also==
+*[[Cellobiohydrolase 3D structures|Cellobiohydrolase 3D structures]]
+*[[Glucanase 3D structures|Glucanase 3D structures]]
 == References ==
 <references/>
@@ Line 36: / Line 40: @@
 </StructureSection>
 [[Category: Atcc 13631]]
+[[Category: Large Structures]]
 [[Category: Harris, M]]
 [[Category: Jones, T A]]

1egn

From Proteopedia

Revision as of 09:25, 6 November 2019

CELLOBIOHYDROLASE CEL7A (E223S, A224H, L225V, T226A, D262G) MUTANT

Structural highlights

Function

Evolutionary Conservation

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

Views

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