Picomolar Inhibitors as Transition-State Probes of 5′-Methylthioadenosine Nucleosidases

@article{citeulike:3095532, abstract = {Transition states can be predicted from an enzymes affinity to related transition-state analogues. 52-Methylthioadenosine nucleosidases (MTANs) are involved in bacterial quorum sensing pathways and thus are targets for antibacterial drug design. The transition-state characteristics of six MTANs are compared by analyzing dissociation constants (Kd) with a small array of representative transition-state analogues. These inhibitors mimic early or late dissociative transition states with Kd values in the picomolar range. Our results indicate that the Kd ratio for mimics of early and late transition states are useful in distinguishing between these states. By this criterion, the transition states of Neisseria meningitides and Helicobacter pylori MTANs are early dissociative, whereas Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, and Klebsiella pneumoniae MTANs have late dissociative characters. This conclusion is confirmed independently by the characteristic [12-3H] and [12-14C] kinetic isotope effects (KIEs) of these enzymes. Large [12-3H] and unity [12-14C] KIEs are observed for late dissociative transition states, whereas early dissociative states showed close-to-unity [12-3H] and significant [12-14C] KIEs. Kd values of various MTANs for individual transition-state analogues provide tentative information about transition-state structures due to varying catalytic efficiencies of enzymes. Comparing Kd ratios for mimics of early and late transition states removes limitations inherent to the enzyme and provides a better predictive tool in discriminating between possible transition-state structures.}, address = {Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, 10461, ! Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North, New Zealand, {\S} Carbohydrate Chemistry Team, Industrial Research Ltd., Lower Hutt, New Zealand, {\P}Contributed equally to this work.}, author = {Gutierrez, Jemy A. and Luo, Minkui and Singh, Vipender and Li, Lei and Brown, Rosemary L. and Norris, Gillian and E. and Evans, Gary B. and Furneaux, Richard H. and Tyler, Peter C. and Painter, Gavin F. and Lenz, Dirk H. and Schramm, Vern L. }, citeulike-article-id = {3095532}, doi = {http://dx.doi.org/10.1021/cb700166z}, journal = {ACS Chem. Biol.}, keywords = {drugdiscovery, transitionstate}, month = {November}, number = {11}, pages = {725--734}, posted-at = {2008-08-07 11:58:48}, priority = {0}, title = {Picomolar Inhibitors as Transition-State Probes of 5\&\#x2032;-Methylthioadenosine Nucleosidases}, url = {http://dx.doi.org/10.1021/cb700166z}, volume = {2}, year = {2007} }

TY - JOUR ID - citeulike:3095532 L3 - citeulike-article-id:3095532 TI - Picomolar Inhibitors as Transition-State Probes of 5′-Methylthioadenosine Nucleosidases JF - ACS Chem. Biol. VL - 2 IS - 11 SP - 725 EP - 734 AD - Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, 10461, ! Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North, New Zealand, § Carbohydrate Chemistry Team, Industrial Research Ltd., Lower Hutt, New Zealand, ¶Contributed equally to this work. N2 - Transition states can be predicted from an enzymes affinity to related transition-state analogues. 52-Methylthioadenosine nucleosidases (MTANs) are involved in bacterial quorum sensing pathways and thus are targets for antibacterial drug design. The transition-state characteristics of six MTANs are compared by analyzing dissociation constants (Kd) with a small array of representative transition-state analogues. These inhibitors mimic early or late dissociative transition states with Kd values in the picomolar range. Our results indicate that the Kd ratio for mimics of early and late transition states are useful in distinguishing between these states. By this criterion, the transition states of Neisseria meningitides and Helicobacter pylori MTANs are early dissociative, whereas Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, and Klebsiella pneumoniae MTANs have late dissociative characters. This conclusion is confirmed independently by the characteristic [12-3H] and [12-14C] kinetic isotope effects (KIEs) of these enzymes. Large [12-3H] and unity [12-14C] KIEs are observed for late dissociative transition states, whereas early dissociative states showed close-to-unity [12-3H] and significant [12-14C] KIEs. Kd values of various MTANs for individual transition-state analogues provide tentative information about transition-state structures due to varying catalytic efficiencies of enzymes. Comparing Kd ratios for mimics of early and late transition states removes limitations inherent to the enzyme and provides a better predictive tool in discriminating between possible transition-state structures. KW - drugdiscovery KW - transitionstate AU - Gutierrez, Jemy AU - Luo, Minkui AU - Singh, Vipender AU - Li, Lei AU - Brown, Rosemary AU - Norris, Gillian AU - Evans, Gary AU - Furneaux, Richard AU - Tyler, Peter AU - Painter, Gavin AU - Lenz, Dirk AU - Schramm, Vern PY - 2007/11/20/ UR - http://dx.doi.org/10.1021/cb700166z ER -