Thr/Ser-rich Domain of<i>Aspergillus</i>Glucoamylase Is Essential for Secretion

Goto, Minoru; Shinoda, N.; Oka, Takuji; Sameshima, Yuka; Ekino, Keisuke; Furukawa, Koichi

doi:10.1271/bbb.68.961

Cited by 11 publications

(11 citation statements)

References 10 publications

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“…to connect domain C to the SBD (19), especially because the flexible nature of the linker may allow the catalytic domain to access large areas of the starch granule surface (39). Even though these linkers are vital for correct folding, secretion, and, consequently, activity (15), there are a few cases in which the linkers are absent and the amylases are able to degrade raw starch (18,42). When linkers are present they are characteristically rich in glycine, serine, and threonine (19), as are the IRs linking the RU in L. plantarum ␣-amylase.…”

Section: Discussionmentioning

confidence: 99%

“…These regions are rich in serine and threonine; consequently, they may increase the random coil regions and perhaps the mobility of the RUs in the L. plantarum and L. manihotivorans ␣-amylases in contrast with the SBD from L. amylovorus. The flanking regions and intermediary regions have a consensus sequence (TTSDSSSSSSST TTET) that resembles the serine-threonine rich O-glycosylated Gp-I domain of glucoamylase I from Aspergillus niger involved in maintenance of protein structure against stress, adsorption onto raw starch granules, and secretion (7,14,15,23,27,38).…”

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confidence: 99%

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Starch-Binding Domain Affects Catalysis in Two Lactobacillus α-Amylases

Rodríguez‐Sanoja

Ruiz²,

Guyot³

et al. 2005

Appl Environ Microbiol

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A new starch-binding domain (SBD) was recently described in ␣-amylases from three lactobacilli (Lactobacillus amylovorus, Lactobacillus plantarum, and Lactobacillus manihotivorans). Usually, the SBD is formed by 100 amino acids, but the SBD sequences of the mentioned lactobacillus ␣-amylases consist of almost 500 amino acids that are organized in tandem repeats. The three lactobacillus amylase genes share more than 98% sequence identity. In spite of this identity, the SBD structures seem to be quite different. To investigate whether the observed differences in the SBDs have an effect on the hydrolytic capability of the enzymes, a kinetic study of L. amylovorus and L. plantarum amylases was developed, with both enzymes acting on several starch sources in granular and gelatinized forms. Results showed that the amylolytic capacities of these enzymes are quite different; the L. amylovorus ␣-amylase is, on average, 10 times more efficient than the L. plantarum enzyme in hydrolyzing all the tested polymeric starches, with only a minor difference in the adsorption capacities.␣-Amylases (1,4-␣-D-glucan-4 glucanohydrolase; EC 3.2.1.1) are a widespread group of enzymes that catalyze the hydrolysis of the ␣-1,4 glycosidic linkages of raw and soluble starch, thereby generating smaller dextrins and oligosaccharides. They are classified into family 13 in the sequence-based classification of glycoside hydrolases (GH-13) (16, 17). They are multidomain proteins that contain, in addition to the catalytic (␤/␣) 8 domain (domain A), domains B and C. Domain B is inserted between the third ␤-strand and the third ␣-helix of the barrel and varies greatly in length and structure (21). Domain C follows the catalytic barrel; this domain is made of ␤-strands and is thought to stabilize the catalytic domain by shielding hydrophobic residues of domain A from the solvent (29). Some of these enzymes contain one noncatalytic domain whose function is generally described as that of a starch-binding domain (SBD).The SBD is a functional domain that can bind granular starch, increasing the local concentration of substrate at the active site of the enzyme, and that may also disrupt the structure of the starch surface, thereby enhancing the amylolytic rate (39, 40). In the primary structure classification of glycoside hydrolases (16, 17; http://afmb.cnrs-mrs.fr/ϳcazy/CAZY/index .html), the carbohydrate-binding modules (CBM) are organized into 39 families, which include several specificities such as cellulose, xylan, chitin, and starch binding. The most generalized and studied family of starch-binding modules is CBM-20. These modules are present in approximately 10% of amylolytic enzymes from GH-13 (almost all cyclomaltodextrin glucanotransferase, in a few ␣-amylases, and in maltotetraohydrolases, maltopentaohydrolases, maltogenic ␣-amylases, and acarviose transferases), GH-14 (some ␤-amylases), and GH-15 (most fungal glucoamylases). This domain is positioned at the C-terminal end of proteins except for the glucoamylase from Rhizopus oryzae and the The...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Starch-Binding Domain Affects Catalysis in Two Lactobacillus α-Amylases

Rodríguez‐Sanoja

Ruiz²,

Guyot³

et al. 2005

Appl Environ Microbiol

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“…Furthermore, the same Gp-I region was found to be crucial for correct folding of the enzyme. 23 Both genes encoding the native glucoamylase from A. awamori, GAI, and pumping or stirring of the slurry. [13][14][15] The CBP of raw starch would require recombinant S. cerevisiae strains to produce sufficient quantities of raw starch degrading enzymes to ensure hydrolysis at a high substrate loading and at moderate temperatures.…”

Section: Onsolidated Bioprocessing (Cbp)mentioning

confidence: 99%

Designing industrial yeasts for the consolidated bioprocessing of starchy biomass to ethanol

et al. 2013

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“…Up to now, different amylase genes have been identified and isolated from different sources and transferred to the laboratory and industrial yeast strains to enhance CBP. The transferred genes included the wild type and codon-optimized glucoamylase (GAI) and α amylase genes (Goto et al, 1994(Goto et al, , 2004Murai et al, 1998;Eksteen et al, 2003;Shigechi et al 2004a,b;Khaw et al, 2006a,b;Yamada et al, 2009;Favaro et al, 2010aFavaro et al, ,b, 2012c. These genetic manipulations critically increased the ethanol production in the CBP system (0.42-0.55 g ethanol/g of consumed sugars).…”

Section: Cbp In Starchy Biomass (Amylolytic Yeasts)mentioning

confidence: 99%

Advances in consolidated bioprocessing systems for bioethanol and butanol production from biomass: a comprehensive review

2015

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HIGHLIGHTS Various CBP strategies have been discussed. Recently, lignocellulosic biomass as the most abundant renewable resource has been widely considered for bioalcohols production. However, the complex structure of lignocelluloses requires a multi-step process which is costly and time consuming. Although, several bioprocessing approaches have been developed for pretreatment, saccharification and fermentation, bioalcohols production from lignocelluloses is still limited because of the economic infeasibility of these technologies. This cost constraint could be overcome by designing and constructing robust cellulolytic and bioalcohols producing microbes and by using them in a consolidated bioprocessing (CBP) system. This paper comprehensively reviews potentials, recent advances and challenges faced in CBP systems for efficient bioalcohols (ethanol and butanol) production from lignocellulosic and starchy biomass. The CBP strategies include using native single strains with cellulytic and alcohol production activities, microbial co-cultures containing both cellulytic and ethanologenic microorganisms, and genetic engineering of cellulytic microorganisms to be alcohol-producing or alcohol producing microorganisms to be cellulytic. Moreover, high-throughput techniques, such as metagenomics, metatranscriptomics, next generation sequencing and synthetic biology developed to explore novel microorganisms and powerful enzymes with high activity, thermostability and pH stability are also discussed. Currently, the CBP technology is in its infant stage, and ideal microorganisms and/or conditions at industrial scale are yet to be introduced. So, it is essential to bring into attention all barriers faced and take advantage of all the experiences gained to achieve a high-yield and low-cost CBP process.

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Thr/Ser-rich Domain ofAspergillusGlucoamylase Is Essential for Secretion

Cited by 11 publications

References 10 publications

Starch-Binding Domain Affects Catalysis in Two Lactobacillus α-Amylases

Starch-Binding Domain Affects Catalysis in Two Lactobacillus α-Amylases

Designing industrial yeasts for the consolidated bioprocessing of starchy biomass to ethanol

Advances in consolidated bioprocessing systems for bioethanol and butanol production from biomass: a comprehensive review

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