Nasihah Musa - Academia.edu (original) (raw)
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Copper is a transition metal which is essentially needed in living things. It plays various roles... more Copper is a transition metal which is essentially needed in living things. It plays various roles such as cofactor for enzymes which are important in cellular processes. However, high concentration of copper will lead to toxicity. Living organisms have metal homeostasis mechanisms in order to overcome such adversities caused by metals.In bacteria, such mechanisms help to stabilize cellular copper concentrations. To date,nine classes of copper regulation have been documented and classified based on the organisms from which they have been found. CsoR copper regulation is the most recently discovered mechanism. To date, only three CsoR proteins (from Thermus thermophilus, Mycobacterium tuberculosis and Streptomyces lividans) are structurally and functionally characterized. Hence, the effort of finding and characterizing more of these proteins from other bacterial strains are important to gain more significant comparisons of this protein across different bacterial taxa. A good platform ...
Background: Klebsiella pneumoniae plays a major role in causing nosocomial infection in immunocom... more Background: Klebsiella pneumoniae plays a major role in causing nosocomial infection in immunocompromised patients. Medical inflictions by the pathogen can range from respiratory and urinary tract infections, septicemia and primarily, pneumonia. As more K. pneumoniae strains are becoming highly resistant to various antibiotics, treatment of this bacterium has been rendered more difficult. This situation, as a consequence, poses a threat to public health. Hence, identification of possible novel drug targets against this opportunistic pathogen need to be undertaken. In the complete genome sequence of K. pneumoniae MGH 78578, approximately one-fourth of the genome encodes for hypothetical proteins (HPs). Due to their low homology and relatedness to other known proteins, HPs may serve as potential, new drug targets. Results: Sequence analysis on the HPs of K. pneumoniae MGH 78578 revealed that a particular HP termed KPN_00953 (YcbK) contains a M15_3 peptidases superfamily conserved domain. Some members of this superfamily are metalloproteases which are involved in cell wall metabolism. BLASTP similarity search on KPN_00953 (YcbK) revealed that majority of the hits were hypothetical proteins although two of the hits suggested that it may be a lipoprotein or related to twin-arginine translocation (Tat) pathway important for transport of proteins to the cell membrane and periplasmic space. As lipoproteins and other components of the cell wall are important pathogenic factors, homology modeling of KPN_00953 was attempted to predict the structure and function of this protein. Three-dimensional model of the protein showed that its secondary structure topology and active site are similar with those found among metalloproteases where two His residues, namely His169 and His209 and an Asp residue, Asp176 in KPN_00953 were found to be Zn-chelating residues. Interestingly, induced expression of the cloned KPN_00953 gene in lipoprotein-deficient E. coli JE5505 resulted in smoother cells with flattened edges. Some cells showed deposits of film-like material under scanning electron microscope.
Copper is a transition metal which is essentially needed in living things. It plays various roles... more Copper is a transition metal which is essentially needed in living things. It plays various roles such as cofactor for enzymes which are important in cellular processes. However, high concentration of copper will lead to toxicity. Living organisms have metal homeostasis mechanisms in order to overcome such adversities caused by metals.In bacteria, such mechanisms help to stabilize cellular copper concentrations. To date,nine classes of copper regulation have been documented and classified based on the organisms from which they have been found. CsoR copper regulation is the most recently discovered mechanism. To date, only three CsoR proteins (from Thermus thermophilus, Mycobacterium tuberculosis and Streptomyces lividans) are structurally and functionally characterized. Hence, the effort of finding and characterizing more of these proteins from other bacterial strains are important to gain more significant comparisons of this protein across different bacterial taxa. A good platform ...
Background: Klebsiella pneumoniae plays a major role in causing nosocomial infection in immunocom... more Background: Klebsiella pneumoniae plays a major role in causing nosocomial infection in immunocompromised patients. Medical inflictions by the pathogen can range from respiratory and urinary tract infections, septicemia and primarily, pneumonia. As more K. pneumoniae strains are becoming highly resistant to various antibiotics, treatment of this bacterium has been rendered more difficult. This situation, as a consequence, poses a threat to public health. Hence, identification of possible novel drug targets against this opportunistic pathogen need to be undertaken. In the complete genome sequence of K. pneumoniae MGH 78578, approximately one-fourth of the genome encodes for hypothetical proteins (HPs). Due to their low homology and relatedness to other known proteins, HPs may serve as potential, new drug targets. Results: Sequence analysis on the HPs of K. pneumoniae MGH 78578 revealed that a particular HP termed KPN_00953 (YcbK) contains a M15_3 peptidases superfamily conserved domain. Some members of this superfamily are metalloproteases which are involved in cell wall metabolism. BLASTP similarity search on KPN_00953 (YcbK) revealed that majority of the hits were hypothetical proteins although two of the hits suggested that it may be a lipoprotein or related to twin-arginine translocation (Tat) pathway important for transport of proteins to the cell membrane and periplasmic space. As lipoproteins and other components of the cell wall are important pathogenic factors, homology modeling of KPN_00953 was attempted to predict the structure and function of this protein. Three-dimensional model of the protein showed that its secondary structure topology and active site are similar with those found among metalloproteases where two His residues, namely His169 and His209 and an Asp residue, Asp176 in KPN_00953 were found to be Zn-chelating residues. Interestingly, induced expression of the cloned KPN_00953 gene in lipoprotein-deficient E. coli JE5505 resulted in smoother cells with flattened edges. Some cells showed deposits of film-like material under scanning electron microscope.