Dr. Saumen Datta

Current Research Interest

Structural probing into biological system by X-ray diffraction methods.

Type III Secretion Systems
Type III secretion systems (T3SS) are found in a large number of gram-negative pathogenic bacteria.  These systems allow the bacteria to deliver some bacterial proteins known as virulent factors or effectors directly into the host cells. Bacteria use a needle like apparatus or machine to deliver these virulent proteins. Although, the proteins make the T3SS machine are almost conserved amongst different pathogenic species, the effector/translocator proteins they deliver are of heterologos in sequence. Although, there is a great diversity amongst their targets and the effects they induce in the host cells, functionally two major themes emerge. The first one is the modulation of cytoskeletal dynamics for bacterial entry into the host cell or to block phagocytosis. The other one and the second theme of action is to subvert or disrupt the several cell functions. In majority of these virulent activity effectors utilize their three dimensional structural similarity with the host proteins. Interestingly secretion of effector molecules by T3SS is one or two chaperone mediated. The three dimensional structural characterization of T3SS effectors, chaperones as well as effector-chaperone complexes is expected to elicit the hidden mechanism of this system.

Bacterial collagenase
Collagenase, a zinc metalloproteinase, catalyzes the hydrolysis of native collagens. More information is available for the large family of mammalian collagenase. Approximately 28 human matrix metalloproteinases (MMPs) with four of their endogenous tissue inhibitors (TIMPs) act together to control the focal proteolysis of extracellular matrix. When unchecked, they can cause arthritis, promote tumor invasion and many others. In the neurons of the adult brain several collagenase/inhibitor systems are expressed and are responsive to changes in neuronal activity. A plethora of mammalian MMP structures, most of them are collagenase, are now available and reveal distinct morphologies and pathologies. However, there is very little known about the structure and catalytic activity of collagenase from microorganisms. My laboratory thus aims to do structural characterization of bacterial collagenases. Bacterial collagenases are being used widely from clinical therapy like wound healing, retainment of placenta, gene therapy to industry like food and leather.