Functional roles of C-terminal extension (CTE) of salt-dependent peptidase activity of the Natrialba magadii extracellular protease (NEP)

MAREM, ALYNE; OKAMOTO, DEBORA N.; OLIVEIRA, LILIAN C.G.; RUIZ, DIEGO M.; PAGGI, ROBERTO A.; KONDO, MARCIA Y.; GOUVEA, IURI E.; JULIANO, MARIA A.; DE CASTRO, ROSANA E.; JULIANO, LUIZ; ICIMOTO, MARCELO Y.

INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES

ELSEVIER SCIENCE BV

Año: 2018 vol. 113 p. 1134 - 1141

0141-8130

Nep (Natrialba magadii extracellular protease) is a halolysin-like peptidase secreted by the haloalkaliphilicarchaeonNatrialba magadii. Many extracellular proteases have been characterized from archaea to bacteria asadapted to hypersaline environments retaining function and stability until 4.0 M NaCl. As observed in other se-creted halolysins, this stability can be related to the presence of a C-terminal extension (CTE) sequence. In thepresent work, we compared the biochemical properties of recombinant Nep protease with the truncated format the 134 amino acids CTE (NepΔCTE), that was more active in 4 M NaCl than the non-truncated wild type en-zyme. Comparable to the wild type, NepΔCTE protease is irreversibly inactivated at low salt solutions. The sub-strate specificity of the truncated NepΔCTE was similar to that of wild type form as demonstrated by acombinatorial library of FRET substrates. The enzyme stability, the effect of different salts and the thermodynam-ics assays using different lengths of substrates demonstrated similarities between the two forms. Altogether,these data provide further information on the stability and structural determinants of halolysins under differentsalinities, especially concerning the enzymatic behavior.