The isolated proteolytic domain of Escherichia coli ATP-dependent protease Lon exhibits the peptidase activity

AbstractSelective protein degradation is an energy-dependent process performed by high-molecular-weight proteases. The activity of proteolytic components of these enzymes is coupled to the ATPase activity of their regulatory subunits or domains. Here, we obtained the proteolytic domain of Escherichia coli protease Lon by cloning the corresponding fragment of the lon gene in pGEX-KG, expression of the hybrid protein, and isolation of the proteolytic domain after hydrolysis of the hybrid protein with thrombin. The isolated proteolytic domain exhibited almost no activity toward protein substrates (casein) but hydrolyzed peptide substrates (melittin), thereby confirming the importance of the ATPase component for protein hydrolysis. Protease Lon and its proteolytic domain differed in the efficiency and specificity of melittin hydrolysis

Heavy Quarks and Heavy Quarkonia as Tests of Thermalization

We present here a brief summary of new results on heavy quarks and heavy quarkonia from the PHENIX experiment as presented at the "Quark Gluon Plasma Thermalization" Workshop in Vienna, Austria in August 2005, directly following the International Quark Matter Conference in Hungary.Comment: 8 pages, 5 figures, Quark Gluon Plasma Thermalization Workshop (Vienna August 2005) Proceeding

Crystal structure of the N-terminal domain of E. coli Lon protease

We report here the first crystal structure of the N-terminal domain of an A-type Lon protease. Lon proteases are ubiquitous, multidomain, ATP-dependent enzymes with both highly specific and non-specific protein binding, unfolding, and degrading activities. We expressed and purified a stable, monomeric 119-amino acid N-terminal subdomain of the Escherichia coli A-type Lon protease and determined its crystal structure at 2.03 Å (Protein Data Bank [PDB] code 2ANE). The structure was solved in two crystal forms, yielding 14 independent views. The domain exhibits a unique fold consisting primarily of three twisted β-sheets and a single long α-helix. Analysis of recent PDB depositions identified a similar fold in BPP1347 (PDB code 1ZBO), a 203-amino acid protein of unknown function from Bordetella parapertussis, crystallized as part of a structural genomics effort. BPP1347 shares sequence homology with Lon N-domains and with a family of other independently expressed proteins of unknown functions. We postulate that, as is the case in Lon proteases, this structural domain represents a general protein and polypeptide interaction domain

Structure of the N-terminal fragment of Escherichia coli Lon protease

The medium-resolution structure of the N-terminal fragment of E. coli Lon protease shows that this part of the enzyme consists of two compact domains and a very long α-helix