Differential secretion of isoforms of Serratia marcescens extracellular nuclease

Y. Suh, M. Alpaugh, K. L. Krause, M. J. Benedik

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Extracellular secretion of the Serratia marcescens nuclease occurs in a two-step process: (i) rapidly to the periplasm via a signal sequence- dependent pathway and then (ii) slowly to the extracellular growth medium without cell lysis. There are two major isoforms of the nuclease in the culture supernatant of S. marcescens. We have isolated, purified, and determined the sequences of both isoforms. The first isoform, the mature nuclease (Sm2), is the result of signal sequence processing. The second isoform (Sm1) has three additional amino acids missing from the N terminus of the mature nuclease. Sm1 starts to appear extracellularly only during prolonged growth of a culture (16 to 48 h), probably because of cell lysis. However, pulse-chase experiments show that it is made early with Sm2 but is not secreted efficiently.

Original languageEnglish (US)
Pages (from-to)4083-4088
Number of pages6
JournalApplied and Environmental Microbiology
Issue number11
StatePublished - 1995
Externally publishedYes

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Food Science
  • Biotechnology
  • Ecology


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