Disulfide bond structure and domain organization of yeast beta(1,3)-glucanosyltransferases involved in cell wall biogenesis
Articolo
Data di Pubblicazione:
2008
Citazione:
Disulfide bond structure and domain organization of yeast beta(1,3)-glucanosyltransferases involved in cell wall biogenesis / L. Popolo, E. Ragni, C. Carotti, O. Palomares, R. Aardema, J.W. Back, H.L. Dekker, L.J. de Koning, L. de Jong, C.G. de Koster. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - 283:27(2008), pp. 18553-18565. [10.1074/jbc.M801562200]
Abstract:
The Gel/Gas/Phr family of fungal β(1,3)-glucanosyltransferases plays an important role in cell wall biogenesis by processing the main component β(1,3)-glucan. Two subfamilies are distinguished depending on the presence or absence of a C-terminal cysteine-rich domain, denoted "Cys-box." The N-terminal domain (NtD) contains the catalytic residues for transglycosidase activity and is separated from the Cys-box by a linker region. To obtain a better understanding of the structure and function of the Cys-box-containing subfamily, we identified the disulfide bonds in Gas2p from Saccharomyces cerevisiae by an improved mass spectrometric methodology. We mapped two separate intra-domain clusters of three and four disulfide bridges. One of the bonds in the first cluster connects a central Cys residue of the NtD with a single conserved Cys residue in the linker. Site-directed mutagenesis of the Cys residue in the linker resulted in an endoplasmic reticulum precursor that was not matured and underwent a gradual degradation. The relevant disulfide bond has a crucial role in folding as it may stabilize the NtD and facilitate its interaction with the C-terminal portion of a Gas protein. The four disulfide bonds in the Cys-box are arranged in a manner consistent with a partial structural resemblance with the plant X8 domain, an independent carbohydrate-binding module that possesses only three disulfide bonds. Deletion of the Cys-box in Gas2 or Gas1 proteins led to the formation of an NtD devoid of any enzymatic activity. The results suggest that the Cys-box is required for proper folding of the NtD and/or substrate binding.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
L. Popolo, E. Ragni, C. Carotti, O. Palomares, R. Aardema, J.W. Back, H.L. Dekker, L.J. de Koning, L. de Jong, C.G. de Koster
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