Alpha-amylase starch binding domains: cooperative effects of binding to starch granules of multiple tandemly arranged domains.

The Lactobacillus amylovorus alpha-amylase starch binding domain (SBD) is a functional domain responsible for binding to insoluble starch. Structurally, this domain is dissimilar from other reported SBDs because it is composed of five identical tandem modules of 91 amino acids each. To understand adsorption phenomena specific to this SBD, the importance of their modular arrangement in relationship to binding ability was investigated.

The membrane channel-forming colicin A: synthesis, secretion, structure, action and immunity.

The study of colicin release from producing cells has revealed a novel mechanism of secretion. Instead of a built-in 'tag', such as a signal peptide containing information for secretion, the mechanism employs coordinate expression of a small protein which causes an increase in the envelope permeability, resulting in the release of the colicin as well as other proteins. On the other hand, the mechanism of entry of colicins into sensitive cells involves the same three stages of protein translocation that have been demonstrated for various cellular organelles.

The complete nucleotide sequence of the colicinogenic plasmid ColA. High extent of homology with ColE1.

The complete nucleotide sequence of the colicinogenic plasmid ColA has been determined. The plasmid DNA consists of 6720 bp (molecular weight 4.48 X 10(6].

Identification of functional regions of the colicinogenic plasmid ColA.

ColA is a colicinogenic plasmid of 6.72 kb. It is compatible with ColE1 but not with ColK.

A molecular genetic approach to the functioning of the immunity protein to colicin A.

A plasmid (pColAF1), derived from pColA, and lacking the region encoding Cai (colicin A immunity protein) and Cal (colicin A lysis protein) has been constructed. The strains carrying pColAF1 produce normal amounts of colicin A which remains in the cell cytoplasm and does not result in loss of viability. Similar results have also been obtained for transposon insertion mutants lacking Cai.