| Full text | |
| Author(s): Show less - |
Domingues, Mariane Noronha
;
Moreira Souza, Flavio Henrique
;
Vieira, Plinio Salmazo
;
Bueno de Morais, Mariana Abrahao
[1]
;
Zanphorlin, Leticia Maria
[1]
;
dos Santos, Camila Ramos
[1]
;
Siqueira Pirolla, Renan Augusto
;
Honorato, Rodrigo Vargas
[2]
;
Lopes de Oliveira, Paulo Sergio
[2]
;
Gozzo, Fabio Cesar
[3]
;
Murakami, Mario Tyago
[1]
Total Authors: 11
|
| Affiliation: | [1] Brazilian Bioethanol Sci & Technol Lab, BR-13083970 Campinas, SP - Brazil
[2] Brazilian Ctr Res Energy & Mat, Brazilian Biosci Natl Lab, BR-13083970 Campinas, SP - Brazil
[3] Univ Estadual Campinas, Dalton Mass Spectrometry Lab, BR-13083970 Campinas, SP - Brazil
Total Affiliations: 3
|
| Document type: | Journal article |
| Source: | Journal of Biological Chemistry; v. 293, n. 35, p. 13636-13649, AUG 31 2018. |
| Web of Science Citations: | 2 |
| Abstract | |
The classical microbial strategy for depolymerization of -mannan polysaccharides involves the synergistic action of at least two enzymes, endo-1,4--mannanases and -mannosidases. In this work, we describe the first exo--mannanase from the GH2 family, isolated from Xanthomonas axonopodis pv. citri (XacMan2A), which can efficiently hydrolyze both manno-oligosaccharides and -mannan into mannose. It represents a valuable process simplification in the microbial carbon uptake that could be of potential industrial interest. Biochemical assays revealed a progressive increase in the hydrolysis rates from mannobiose to mannohexaose, which distinguishes XacMan2A from the known GH2 -mannosidases. Crystallographic analysis indicates that the active-site topology of XacMan2A underwent profound structural changes at the positive-subsite region, by the removal of the physical barrier canonically observed in GH2 -mannosidases, generating a more open and accessible active site with additional productive positive subsites. Besides that, XacMan2A contains two residue substitutions in relation to typical GH2 -mannosidases, Gly(439) and Gly(556), which alter the active site volume and are essential to its mode of action. Interestingly, the only other mechanistically characterized mannose-releasing exo--mannanase so far is from the GH5 family, and its mode of action was attributed to the emergence of a blocking loop at the negative-subsite region of a cleft-like active site, whereas in XacMan2A, the same activity can be explained by the removal of steric barriers at the positive-subsite region in an originally pocket-like active site. Therefore, the GH2 exo--mannanase represents a distinct molecular route to this rare activity, expanding our knowledge about functional convergence mechanisms in carbohydrate-active enzymes. (AU) | |
| FAPESP's process: | 16/06509-0 - Understanding the enzymatic system involved in the degradation and utilization of xyloglucans from the plant pathogen Xanthomonas axonopodis pv. citri |
| Grantee: | Plínio Salmazo Vieira |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 15/26982-0 - Exploring novel strategies for depolymerization of plant cell-wall polysaccharides: from structure, function and rational design of glycosyl hydrolases to biological implications and potential biotechnological applications |
| Grantee: | Mário Tyago Murakami |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 16/19995-0 - Analysis of structural and functional diversity of GH43 enzymes from Xanthomonas axonopodis pv. citri: biological implications and potential biotechnological applications |
| Grantee: | Mariana Abrahão Bueno de Morais |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 13/24622-0 - Elucidation of the mechanistic basis of family GH62 present in organisms specialized in the degradation of plant biomass |
| Grantee: | Flavio Henrique Moreira de Souza |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |