| Autor: |
Broome-Smith, Jenny K., Edelman, Alex, Yousif, Samira, Spratt, Brain G. |
| Předmět: |
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| Zdroj: |
European Journal of Biochemistry; 3/1/85, Vol. 147 Issue 2, p437-446, 10p |
| Abstrakt: |
Penicillin-binding proteins 1A and 1B of Escherichia coli are the major peptidoglycan transglycoslase-transpeptidases that catalyse the polymerisation and insertion of peptidoglycan predursors into bacterial cell ponA gene, encoding penicillin-binding protein 1A, was determined. The sequence predicted that penicillin-binding protein 1A had a relative molecular mass of 93500 (850 amino acids). The amino-terminus of the protein an the features of a signal peptide but it is not known if this peptide is removed during insertion of the protein into the cytoplasmic membrane. The nucleotide sequence of a 2758-base-pair fragment of DNA that contained the ponB gene, encoding penicillin-binding protein 1B, was also determined. Penicillin-binding protein 1B consists of two major components which were shown to result form the use of alternative sites for the initiation of traslation. The large and small forms of penicillin-binding protein 1B were predicted to have relative molecular masses of 94100 and 88800(844 and 799 amino acids). The amino acid sequences of penicillin -binding proteins 1A and 1B could be aligned if two large gaps were introduced into the latter sequence and the two proteins then showed about 30% identity. The amino acid sequences of the proteins showed no extensive similarity to the sequences of penicillin-binding proteins 3 ro 5, or to the class A class C β-lactamases. Two sort regions fo amino acid similarity were, however, found between penicillin-binding proteins 1A and 1B and the other penicillin-binding proteins and β-lactamases. One of these included the predicted active-site serine residue which was located towards the middle of the sequences of penicillin-binding proteins 1A, 1B and 3, within the conserved sequence Gly-Ser-Xaa-Xaa-Lys-Pro. The other region was 19-40 residues to the amino-terminal side of the active-site serine and may be part of a conserved penicillin-binding site in these proteins. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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