Journal:Acta Cryst F:S2053230X18016217
From Proteopedia
The structure of Mycobacterium tuberculosis HtrA reveals an auto-regulatory mechanismArvind Kumar Gupta, Debashree Behera and Balasubramanian Gopal [1] Molecular Tour A common structural feature of HtrA proteases is that of a trypsin-like serine protease domain attached to one or more PDZ domains. An in silico analysis of the topological arrangement of these proteases suggests that they are likely to adopt a similar Nin-Cout conformation with one transmembrane helix. Given substantial sequence and structural conservation, the precise roles as well as the rationale for multiple HtrA paralogues in a bacterium are difficult to predict. This aspect is of particular significance to M. tuberculosis as HtrA enzymes govern virulence but the molecular details remain unclear. The crystal structure of M. tuberculosis HtrA (ΔTM HtrA) that was determined at 1.83 Å resolution. We note that this enzyme exhibits both monomeric as well as trimeric forms in solution. The structure reveals a conformation that would require minor structural alterations for proteolytic activity. Structural features thus suggest that M. tuberculosis HtrA is a regulated protease as opposed to the two other paralogues, PepD and PepA. This essential enzyme is thus likely to be involved in specific signal transduction role as opposed to housekeeping in the recognition and degradation of partially folded or misfolded proteins. The was determined at a resolution of 1.83Å (PDB ID: 6ieo). In this crystal form, there is one molecule of HtrA in the asymmetric unit. The structure of the periplasmic domain reveals one (226-436; colored in royalblue) flexibly tethered to the (443-528; in gold) at the C-terminal end. The (Alpha Helices, Beta Strands , Loops , Turns) referred to as the N-terminal and C-terminal β-barrel. References
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