2c4n
From Proteopedia
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'''NAGD FROM E.COLI K-12 STRAIN''' | '''NAGD FROM E.COLI K-12 STRAIN''' | ||
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[[Category: Dunaway-Mariano, D.]] | [[Category: Dunaway-Mariano, D.]] | ||
[[Category: Tremblay, L W.]] | [[Category: Tremblay, L W.]] | ||
| - | [[Category: | + | [[Category: Carbohydrate metabolism]] |
| - | [[Category: | + | [[Category: Had superfamily]] |
| - | [[Category: | + | [[Category: Hydrolase]] |
| - | [[Category: | + | [[Category: Nagd]] |
| - | [[Category: | + | [[Category: Nucleotide phosphatase]] |
| - | [[Category: | + | [[Category: Ump phosphatase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 21:14:39 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 18:14, 3 May 2008
NAGD FROM E.COLI K-12 STRAIN
Overview
The HAD superfamily is a large superfamily of proteins which share a conserved core domain that provides those active site residues responsible for the chemistry common to all family members. The superfamily is further divided into the four subfamilies I, IIA, IIB, and III, based on the topology and insertion site of a cap domain that provides substrate specificity. This structural and functional division implies that members of a given HAD structural subclass may target substrates that have similar structural characteristics. To understand the structure/function relationships in all of the subfamilies, a type IIA subfamily member, NagD from Escherichia coli K-12, was selected (type I, IIB, and III members have been more extensively studied). The structure of the NagD protein was solved to 1.80 A with R(work) = 19.8% and R(free) = 21.8%. Substrate screening and kinetic analysis showed NagD to have high specificity for nucleotide monophosphates with k(cat)/K(m) = 3.12 x 10(4) and 1.28 x 10(4) microM(-)(1) s(-)(1) for UMP and GMP, respectively. This specificity is consistent with the presence of analogues of NagD that exist as fusion proteins with a nucleotide pyrophosphatase from the Nudix family. Docking of the nucleoside substrate in the active site brings it in contact with conserved residues from the cap domain that can act as a substrate specificity loop (NagD residues 144-149) in the type IIA subfamily. NagD and other subfamily IIA and IIB members show the common trait that substrate specificity and catalytic efficiencies (k(cat)/K(m)) are low (1 x 10(4) M(-)(1) s(-)(1)) and the boundaries defining physiological substrates are somewhat overlapping. The ability to catabolize other related secondary metabolites indicates that there is regulation at the genetic level.
About this Structure
2C4N is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Structure and activity analyses of Escherichia coli K-12 NagD provide insight into the evolution of biochemical function in the haloalkanoic acid dehalogenase superfamily., Tremblay LW, Dunaway-Mariano D, Allen KN, Biochemistry. 2006 Jan 31;45(4):1183-93. PMID:16430214 Page seeded by OCA on Sat May 3 21:14:39 2008
