Stereochemical course and structure of the products of the enzymic action of endo-1,3-1,4-<i>β</i>-<scp>d</scp>-glucan 4-glucanohydrolase from <i>Bacillus licheniformis</i>

Malet, Carles; Jiménez‐Barbero, Jesús; Bernabé, Manuel; Brosa, Carme; Planas, Antoni

doi:10.1042/bj2960753

Cited by 69 publications

(49 citation statements)

References 36 publications

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“…5) suggests that the LamA enzyme could also have a retaining stereochemical course of hydrolytic action (Malet et al, 1993). This mechanism requires two functional groups present in the correct spacial setting.…”

Section: Discussionmentioning

confidence: 99%

Highly thermostable endo-1,3-β -glucanase (laminarinase) Lam A from Thermotoga neapolitana: nucleotide sequence of the gene and characterization of the recombinant gene product

et al. 1997

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The nucleotide sequence of clone p n 2 6 (3786 bp), containing the gene for 1,3-pglucanase LamA (laminarinase) from Tnermofoga neapolitana, was determined. It contains an ORF encoding a protein of 646 aa (73328 Da). The central part of the protein is homologous to the complete catalytic domain of bacterial and some eukaryotic endo-l,3-&~-glucanases and belongs to family 16 of glycosyl hydrolases. This domain is flanked on both sides by one copy on each side of a substrate binding domain homologue (family 11). The recombinant laminarinase protein was purified from Escherichia coli host cells in two forms, a 73 kDa and a processed 52 kDa protein, both having high specific activity towards laminarin (3100 and 2600 U mg-l, respectively) and Km values of 2.8 and 2.2 mg mF, respectively. Limited activity on 1,3-1,4-/3-glucan (lichenan) was detected (90 U mg-l). Laminarin was degraded in an endoglucanase modus, yielding glucose, laminaribiose and ltriose as end products. Thus LamA classifies as an endo-l,3(4)-/3=gIucanase (EC 3.2.1.6). The optimum temperature of the enzymes was 95 "C (73 kDa) and 85 "C (52 kDa) at an optimum pH of 62. The superior thermostability of the 73 kDa enzyme is demonstrated by incubation without substrate at 100 "C, where 57% of the initial activity remained after 30 min (82% at 95 OC). Thus, LamA is the most thermostable 1,3-&glucanase described to date.

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Section: Discussionmentioning

confidence: 99%

Highly thermostable endo-1,3-β -glucanase (laminarinase) Lam A from Thermotoga neapolitana: nucleotide sequence of the gene and characterization of the recombinant gene product

et al. 1997

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“…3b). Therefore, the stereochemistry of the reaction as determined for BGLL [15] may be expected to be the same in both BGLM and H(A16-M).…”

Section: Active Sitementioning

confidence: 99%

“…That tile reaction indeed proceeds with retention of configuration was shown biochemically for BGLL [15]. Since the threedimensional structure of this protein was not known, it was unclear whether we were justified to assume identical enzyme mechanisms for BGLM and BGLL.…”

Section: Introductionmentioning

confidence: 99%

Crystal structure of Bacillus licheniformis 1,3‐1,4‐β‐d‐glucan 4‐glucanohydrolase at 1.8 Å resolution

et al. 1995

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The crystal structure of the 1,3-1,4-1~-D-glucan 4-glucanohydrolasoe from Bacillus licheniformis is solved at a resolution of 1.8 A and refined to R = 16.5%. The protein has a similar g-sandwich structure as the homologous enzyme from Bacillus macerans and the hybrid H(A16-M). This demonstrates that the jellyroll fold of these proteins is remarkably rigid and only weakly influenced by crystal contacts. The crystal structure permits to extend mechanistic considerations derived for the B. licheniformis enzyme to the entire class of bacterial 1,3-1,4-1~-nglucan 4-glucanohydrolases.

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“…Therefore, since the rate o" hydrolysis must be greater than that of mutarotation, these substrates are not particularly suitable for stereochemical aaalysis of endo-arabinanases where very rapid mutarotation c" the hydrolysis products (arabinofuranosyl oligosaccharides) as observed to occur. Since several recent reports have desc ibed the successful use of natural polymers as substrates for slereochemical analysis with 1H-NMR [37][38][39], we have empoyed linear (apple) (1 ~ 5)-Ct-L-arabinan for this purpose in ti e current study. Fig.…”

Section: Endo-arabinanasesmentioning

confidence: 99%

Stereochemical course of hydrolysis catalyzed by arabinofuranosyl hydrolases

Pitson¹,

Voragen²,

Beldman³

1996

FEBS Letters

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1~ IntroductionEnzymic hydrolysis of glycosidic linkages occurs via two m ~jor mechanisms, which result in either net retention or inversion of anomeric configuration [1]. Both hydrolytic mechmisms involve general acid catalysis and require two critical reddues (a proton donor and a nucleophile/base), which in m 9st glycosyl hydrolases are aspartate and/or glutamate resid~es 2.1.99)hydrolyse the (1 ~ 5)-C~-L-arabinofuranosyl linkages in linear arabinan in a random pattern, initially releasing arabinotriose and larger arabino-oligosaccharides as the major hydrolysis products [22]. In contrast, C~-L-arabinofuranosidases (a-L-arabinofuranoside arabinofuranohydrolase, EC 3.2.1.55) hydrolyse nonreducing C~-L-arabinofuranosyl residues from arabinofuranosecontaining substrates, releasing arabinose as the only hydrolysis product [21]. Two major types of C~-L-arabinofuranosidases can be classified according to substrate specificity, and are typified by the two enzymes isolated from Aspergillus niger [21,24]. Arabinofuranosidase A is only active against small substrates, like 4-nitrophenyl a-L-arabinofuranoside (pNPA) and short-chain arabino-oligosaccharides, while arabinofuranosidase B has similar activity on these substrates, but is also able to hydrolyse polymeric substrates like branched arabinan and arabinoxylan. Recently, other enzymes have been isolated [25,26] that are specific for arabinofuranosyl residues in arabinoxylan, and are termed arabinoxylan arabinohydrolases ((1 ~4)-[3-D-arabinoxylan arabinofuranohydrolase, EC 3.2.1.) (AXH). The AXH from Aspergillus awamori has been studied in some detail [23,25,27] and found to only cleave arabinofuranose from single-substituted xylopyranosyl residues in the xylan backbone, and has only low activity against substrates like pNPA or branched arabinan. Similar enzymes from B/fidobacterium adolescentis [26] and Trichoderma reesei (R. Kavitha, H. Gruppen and A.G.J. Voragen, unpublished) have also been recently isolated that appear to have a slightly different specificity since they are active against arabinofuranosyl groups linked to double-substituted xylopyranosyl residues, and are therefore termed AXH-d.Apart from studies with the c~-e-arabinofuranosidases from Monilinia fructigena [28,29], there has been little work examining the mechanisms by which these enzymes cleave arabinofuranosyl linkages. In this current study the stereochemical course of hydrolysis catalyzed by endo-(l ~5)-Ot-L-arabina-

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Stereochemical course and structure of the products of the enzymic action of endo-1,3-1,4-β-d-glucan 4-glucanohydrolase from Bacillus licheniformis

Cited by 69 publications

References 36 publications

Highly thermostable endo-1,3-β -glucanase (laminarinase) Lam A from Thermotoga neapolitana: nucleotide sequence of the gene and characterization of the recombinant gene product

Highly thermostable endo-1,3-β -glucanase (laminarinase) Lam A from Thermotoga neapolitana: nucleotide sequence of the gene and characterization of the recombinant gene product

Crystal structure of Bacillus licheniformis 1,3‐1,4‐β‐d‐glucan 4‐glucanohydrolase at 1.8 Å resolution

Stereochemical course of hydrolysis catalyzed by arabinofuranosyl hydrolases

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