Induced circular dichroism study of the aqueous solution complexation of cello-oligosaccharides and related polysaccharides with aromatic dyes

Engle, Allan R.; Purdie, Neil; Hyatt, John A.

doi:10.1016/0008-6215(94)00235-5

Cited by 33 publications

(30 citation statements)

References 32 publications

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“…The interaction between pyranose and aromatic rings in carbohydrate-binding proteins is well established [8,14[, but the nature of this phenomenon is not yet clear. Hydrophobicity has been suggested to play a key role in aromatic ring-sugar interactions and in the CBD-cellulose interaction [4,15]. In this case the difference in hydrophobicity might offer an explc, nation, since the indole side chain of tryptophan is more hydropbobic than the phenol group of tyrosine.…”

Section: Resultsmentioning

confidence: 99%

The difference in affinity between two fungal cellulose‐binding domains is dominated by a single amino acid substitution

et al. 1995

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Cellulose-binding domains (CBDs) form distinct functional units of most cellulolytic enzymes. We have compared the cellulose-binding affinities of the CBDs of ceilobiohydrolase 1 (CBHI) and endoglucanase I (EGI) from the fungus Trichoderma reeseL The CBD of EGI had significantly higher affinity than that of CBHI. Four variants of the CBHI CBD were made in order to identify the residues responsible for the increased affinity in EGI. Most of the difference could be ascribed to a replacement of a tyrosine by a tryptophan on the flat cellulose-binding face.

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Section: Resultsmentioning

confidence: 99%

The difference in affinity between two fungal cellulose‐binding domains is dominated by a single amino acid substitution

et al. 1995

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“…24 This enhancement may be ascribed to higher hydrophobicity of the indole side chain of Trp than that of the phenol ring of Tyr, being a key factor in the aromatic ring-sugar interaction. 25,26 Therefore, the substitutions of Trp for Tyr23 and Tyr32 of AH were expected to improve antisyncytium formation activity by enhancement of Man-a(1-2)-Manbinding affinity. However, our assays found practically no increase.…”

Section: Discussionmentioning

confidence: 99%

Actinohivin: specific amino acid residues essential for anti-HIV activity

et al. 2010

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Actinohivin (AH) is a microbial lectin containing 114 amino acids, which inhibits human immunodeficiency virus (HIV) infection. This effect is brought about by its specific binding to Man-a(1-2)-Man unit(s) of high-mannose type glycan (HMTG) bound to HIV gp120. The recently determined crystal structure of AH suggests that three repeated segments (the residue numbers 1-38, 39-76 and 77-114 for segments 1, 2 and 3, respectively) form three sugar-binding pockets to accommodate Man-a(1-2)-Man units. The strong specific binding of AH to gp120 is considered to be due to multivalent interaction of the three sugar-binding pockets with three HMTGs of gp120 via the 'cluster effect' of lectin. It remains to be seen which residues of the sugar-binding pockets are essential for acceptance of Man-a(1-2)-Man. To identify the amino acid residues critical for anti-HIV effect, we performed mutational analysis. Mutant AHs were subjected to enzyme-linked immunosorbent assay testing for gp120-binding activity and to syncytium formation assay. As a result, it was revealed that Asp15, Tyr23, Leu25, Asn28 and Tyr32 in segment 1, Tyr61 in segment 2 and Tyr99 in segment 3 are essential for anti-HIV activity. The conserved residues, Asp53, Leu63, Asn66 and Tyr70, in segment 2 and, Asp91, Leu101, Asn104 and Tyr108, in segment 3 are also necessary. Furthermore, aromatic residues at positions 23 and 32 are required for creation of potency. These data will be useful for predicting the detailed mechanism of AH-Man-a(1-2)-Man/HMTG/gp120 interaction by computational analysis and for possible development of more potent microbicides for prevention of HIV transmission.

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“…All of these cause spherical cell swelling and lysis. The dyes Calcofluor and Congo Red, which inhibit chitin maturation and crystallization (Kopecka and Gabriel, 1992;Bartnicki-Garcia et al, 1994;Engle et al, 1994), similarly cause cell tip swelling, spherical growth, a thickened cell wall, and lysis (Pancaldi et al, 1984;Roncero and Duran, 1985;Dawe and Morris, unpublished data). Actin colocalizes with the site of new cell wall deposition at the growing hyphal tip in filamentous fungi and at the bud tip in yeast.…”

Section: Discussionmentioning

confidence: 99%

Deletion of nudC, a nuclear migration gene of Aspergillus nidulans, causes morphological and cell wall abnormalities and is lethal.

Chiu¹,

Xiang²,

Dawe³

et al. 1997

MBoC

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Nuclear migration is required for normal development in both higher and lower eukaryotes. In fungi this process is mediated by cytoplasmic dynein. It is believed that this motor protein is anchored to the cell membrane and moves nuclei by capturing and pulling on spindle pole body microtubules. To date, four genes have been identified and shown to be required for this process in Aspergillus nidulans. The nudA and nudG genes, respectively, encode the heavy and light chains of cytoplasmic dynein, and the nudF and nudC gene products encode proteins of 49 and 22 kDa. The precise biochemical functions of the nudF and nudC genes have not yet been identified. In this report we further investigate NUDC protein function by deleting the nudC gene. Surprisingly, although deletion of nudA and nudF affect nuclear migration, deletion of nudC profoundly affected the morphology and composition of the cell wall. Spores of the strain deleted for nudC grew spherically and lysed. The thickness of the cell wall was increased in the deletion mutant and wall polymer composition was abnormal. This phenotype could be repressed by growth on osmotically buffered medium at low temperature. Similar, but less severe, effects were also noted in a strain depleted for NUDC by down-regulation. These results suggest a possible relationship between fungal cell wall biosynthesis and nuclear migration.

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Induced circular dichroism study of the aqueous solution complexation of cello-oligosaccharides and related polysaccharides with aromatic dyes

Cited by 33 publications

References 32 publications

The difference in affinity between two fungal cellulose‐binding domains is dominated by a single amino acid substitution

The difference in affinity between two fungal cellulose‐binding domains is dominated by a single amino acid substitution

Actinohivin: specific amino acid residues essential for anti-HIV activity

Deletion of nudC, a nuclear migration gene of Aspergillus nidulans, causes morphological and cell wall abnormalities and is lethal.

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