S-peptide as a potent peptidyl linker for protein cross-linking by microbial transglutaminase from Streptomyces mobaraensis

Noriho Kamiya, Tsutomu Tanaka, Tsutomu Suzuki, Takeshi Takazawa, Shuji Takeda, Kimitsuna Watanabe, Teruyuki Nagamune

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49 Citations (Scopus)


We have found that ribonuclease S-peptide can work as a novel peptidyl substrate in protein cross-linking reactions catalyzed by microbial transglutaminase (MTG) from Streptomyces mobaraensis. Enhanced green fluorescent protein tethered to S-peptide at its N-terminus (S-tag-EGFP) appeared to be efficiently cross-linked by MTG. As wild-type EGFP was not susceptible to cross-linking, the S-peptide moiety is likely to be responsible for the cross-linking. A site-directed mutation study assigned Gln15 in the S-peptide sequence as the sole acyl donor. Mass spectrometric analysis showed that two Lys residues (Lys5 and Lys11) in the S-peptide sequence functioned as acyl acceptors. We also succeeded in direct monitoring of the cross-linking process by virtue of fluorescence resonance energy transfer (FRET) between S-tag-EGFP and its blue fluorescent color variant (S-tag-EBFP). The protein cross-linking was tunable by either engineering S-peptide sequence or capping the S-peptide moiety with S-protein, the partner protein of S-peptide for the formation of ribonuclease A. The latter indicates that S-protein can be used as a specific inhibitor of S-peptide-directed protein cross-linking by MTG. The controllable protein cross-linking of S-peptide as a potent substrate of MTG will shed new light on biomolecule conjugation.

Original languageEnglish
Pages (from-to)351-357
Number of pages7
JournalBioconjugate Chemistry
Issue number2
Publication statusPublished - 2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Bioengineering
  • Biomedical Engineering
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry


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