Gene Ontology annotation through association of InterPro records with GO terms
Gene Ontology annotation based on Enzyme Commission mapping
Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Electronic Gene Ontology annotations created by ARBA machine learning models
α-glucan remodeling by GH13-domain enzymes shapes fungal cell wall architecture.
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Aah1 and Aah3 are GPI-anchored GH13-family transglycosylases that act redundantly to remodel alpha-glucan chains synthesized by Ags1 into a properly organized matrix.
"...Aah1 and Aah3 function as GH13-family transglycosylases that collaborate nonredundantly with the α-glucan synthase to build a properly organized α-glucan matrix."
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aah1/aah3 double mutant shows severe growth defects, rounded cell shape, delayed division, cell clumping, and dramatically altered cell wall composition.
"Cells lacking both enzymes exhibit severe growth and morphological defects, including rounded shape, delayed division, and cell clumping."
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Solid-state NMR shows alpha-1,3-glucan decreases from 44% to 11% in rigid phase of double mutant, with compensatory beta-glucan increase from 55% to 89%.
"...the double mutant cell walls have dramatically reduced α-1,3-glucan and galactomannan content, with a compensatory increase in β-glucans driven by the activation of the cell integrity pathway."
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Cell wall thickness increases approximately 4-fold in the double mutant, with increased rigidity and reduced polymer mobility.
"These changes correlate with cell wall thickening, increased rigidity, and reduced polymer mobility and hydration."
Two novel, putatively cell wall-associated and glycosylphosphatidylinositol-anchored alpha-glucanotransferase enzymes of Aspergillus niger.
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Purified A. niger AgtA and AgtB, GPI-anchored GH13 proteins, are 4-alpha-glucanotransferases (EC 2.4.1.25). AgtA (A2QTS4) is the ISS donor for Aah1.
"The enzymes, designated AgtA and AgtB, produced new alpha-(1,4)-glycosidic bonds and therefore belong to the group of the 4-alpha-glucanotransferases (EC 2.4.1.25)."
An alpha-amylase homologue, aah3, encodes a GPI-anchored membrane protein required for cell wall integrity and morphogenesis in Schizosaccharomyces pombe.
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Identified four alpha-amylase homologs (aah1-aah4) in S. pombe with putative signal sequences and C-terminal GPI anchor addition signals.
"...four alpha-amylase homologs (Aah1p-Aah4p) have putative signal sequences and C-terminal GPI anchor addition signals."
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Aah3 is a GPI-anchored membrane protein localized in the membrane and cell wall fractions.
"Biochemical analysis showed that Aah3p is an N-glycosylated, GPI-anchored membrane protein localized in the membrane and cell wall fractions."
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Catalytic-residue point mutations in Aah3 abolished function without altering localization, confirming enzymatic activity is required for the cell wall role.
"Expression of aah3 alleles in which the conserved aspartic acid and glutamic acid residues required for hydrolase activity were replaced with alanine residues failed to rescue the morphological and ascal wall defects of aah3Delta cells."