The Primary Structure of L-Asparaginase fromEscherichia coli

Abstract

The carboxymethylated L-asparagitrypsin, chymotrypsin and pepsin, and the Dansyl nase from Escherichia coli A-l -3 was fragmented Edman method. Based on the above results and with cyanogen bromide and the resulting peptides the complete sequences of the tryptic peptides were isolated by using gel filtration on Sephadex from the carboxymethylated L-asparaginase re-G-50 and column chromatography on DE-52. The ported in the previous paper, the whole sequence amino acid sequences of the 7 cyanogen bromide of the enzyme was established. The reported peptides thus obtained were established comsequence consists of 321 amino acid residues and pletely or partially by further fragmentation with its calculated molecular weight is 34080. Die Primärstruktur der L-Asparaginase von Escherichia coliZusammenfassung: Die carboxymethylierte Aufgrund dieser Ergebnisse und der Sequenzen L-Asparaginase von Escherichia coli A-l-3 wurder tryptischen Peptide der carboxymethylierten de mit Bromcyan gespalten und die erhaltenen L-Asparaginase, die in einer früheren Arbeit bePeptide wurden durch Gelfiltration an Sephadex schrieben sind, konnte die vollständige Sequenz G-50 und Säulenchromatographie an DE-52 isodes Enzyms angegeben werden. Sie besteht aus liert. Durch weitere Spaltung mittels Trypsin, 321 Aminosäureresten und hat ein berechnetes Chymotrypsin, Pepsin und die Dansyl-EdmanMolekulargewicht von 34080. Methode wurden die Aminosäuresequenzen von 7 Bromcyanpeptiden teilweise oder vollständig bestimmt.

Analysis of the Escherichia coli gene encoding L-asparaginase II, ansB, and its regulation by cyclic AMP receptor and FNR proteins

“…The amino acid sequence of L-asparaginase II has been previously determined (24). A comparison of these two sequences confirms indirect evidence (40) that they are highly dissimilar; a single region of significant homology, however, is consistent with their likely origin via an ancient gene duplication (19).…”

“…We conclude that L-asparaginase II, as expected for a periplasmic enzyme, has a 22-residue N-terminal signal peptide which is cleaved between residues 22 and 23 ( Fig. 3) to yield a mature protein with an N-terminal leucine residue (24). The (43), is followed by a poly(T) sequence.…”

“…Oligonucleotide probes were based on the amino acid sequence of asparaginase II, determined by Maita and Matsuda (24). Initially, four degenerate probes (14-and 17-mers) corresponding to regions of low codon degeneracy (24).…”

“…1). Amino acids that are single, double, or triple underlined represent single amino acid substitutions, substitutions of two valines for one valine, and an insertion, respectively, when compared with the sequence in reference 24. Fig.…”

“…The second open reading frame (Fig. 3) is identifiable as the ansB-coding sequence (24). Upstream from the codon for the mature N-terminal leucine residue, an initiation codon is present, preceded 6 bp upstream by a strong Shine-Dalgarno sequence.…”