RT Journal Article
T1 Involvement of loop 5 lysine residues and theN-terminal β-hairpin of the ribotoxin hirsutellinA on its insecticidal activity
A1 Olombrada, Miriam
A1 García Ortega, Lucía
A1 Lacadena, Javier
A1 Oñaderra, Mercedes
A1 Gavilanes, José G.
A1 Martínez del Pozo, Álvaro
AB Ribotoxins are cytotoxic members of the family of fungal extracellular ribonucleases best represented by RNase T1. They share a high degree of sequence identity and a common structural fold, including the geometric arrangement of their active sites. However, ribotoxins are larger,with a well-defined N-terminal β-hairpin, and display longer and positively charged unstructured loops. These structural differences account for their cytotoxic properties.Unexpectedly, the discovery of hirsutellin A (HtA), a ribotoxin produced by the invertebrate pathogen Hirsutella thompsonii, showed how it was possible to accommodate these features into a shorter amino acid sequence. Examination of HtA N-terminal β-hairpin reveals differences in terms of length, charge, and spatial distribution. Consequently,four different HtA mutants were prepared and characterized. One of them was the result of deleting this hairpin [Δ(8-15)] while the other three affected single Lys residues in its close spatial proximity (K115E, K118E, and K123E). The results obtained support the general conclusion that HtA active site would show a high degree of plasticity,being able to accommodate electrostatic and structural changes not suitable for the other previously known larger ribotoxins, as the variants described here only presented small differences in terms of ribonucleolytic activity and cytotoxicity against cultured insect cells.
PB De Gruyter
SN 1437-4315 (Online), 1431-6730 (print)
YR 2016
FD 2016
LK https://hdl.handle.net/20.500.14352/24544
UL https://hdl.handle.net/20.500.14352/24544
LA eng
NO Ministerio de Ciencia e Innovación (MICINN)
NO Ministerio de Educación
DS Docta Complutense
RD 5 may 2024