Naslov
Editing of non-cognate aminoacyl adenylates by peptide synthetases

Autori
Pavela-Vrančič, Maja ; Dieckmann, Ralf ; von Dohren, Hans ; Kleinkauf, Horst

Izvornik
Biochemical journal (0264-6021) 342 (1999), Part 3; 715-719

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
non-ribosomal; proof reading

Sažetak
Non-ribosomally formed peptides display both highly conserved and variable amino acid positions, the variations leading to a wide range of peptide families. Activation of the amino acid substrate proceeds in analogy to the ribosomal biosynthetic mechanism generating aminoacyl adenylate and acyl intermediates. To approach the mechanism of fidelity of amino acid selection the stability of the aminoacyl adenylates was studied by employing a continuous coupled spectrophotometric assay. The apo-form of tyrocidine synthetase 1 (apo-TY1) was used, generating an L-phenylalanyl-adenylate (L-Phe?AMP) intermediate stabilized by the interaction of two structural subdomains of the adenylation domain. Adenylates of substrate analogues have shown variable and reduced degrees of stability, thus leading to an enhanced generation of PPi due to hydrolysis and continuous adenylate formation. The available data reflect an increased susceptibility of D-Phe?AMP to degradation, contrary to the extremely stable L-phenylalanyl analogue. Breakdown of the L-phenylalanyl intermediate utilizing 2?-deoxy-ATP as the nucleotide substrate was significantly enhanced compared to the natural analogue. Apo-TY1 engineered at positions involved in adenylate formation showed variable protection of D-Phe?AMP against hydrolysis. The results imply that stability of the aminoacyl intermediates may act as an essential factor in substrate selection and fidelity of non-ribosomal peptide forming systems.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA