Also, AKs has a very important biotechnological potential as it can limit the content of an essential amino acid (lysine) in cereals [22]. Sequence analysis of CaAK suggests that it comprised of two domains, namely, N-terminal conserved amino acid kinase domain (Pfam PF00696) considered as catalytic domain indicates that CaAK belongs to amino

acid kinase family. This domain is further divided into two lobes, the N-lobe making up the Asp-binding site and the C-lobe providing a nucleotide-binding pocket for ATP. A second domain of CaAK represents a C-terminal regulatory domain that includes two Navitoclax research buy small domains belonging to the ACT domain family (Pfam PF01842). ACT domains are ligand-binding domains that are found in a wide variety of regulated proteins [23] and [24]. The structural and biochemical studies of AKs from different organisms highlighted the molecular basis of the diversity of allosteric regulation and the many structural faces of AKs sensitive to the concerted learn more inhibition [19] and [25]. Based on

the crystallographic structures AKs are categorized into three classes. Class I contains the homo-dimeric enzymes from E.coli, Methanococcus jannaschii and A. thaliana with one catalytic domain and two ACT domains per monomer [26], [27] and [28]. The dimerization is mediated by the association of the ACT domains. Class II contains to the hetero-tetrameric enzyme from C.glutamicum with one catalytic domain and two ACT domains per α-subunit and two ACT domains per β-subunit [29]. The oligomerization involves strong association of the catalytic domain of the α-subunits and the interaction of the ACT domains of α and β-subunits. Class III contains the homo-dimeric enzyme from Synechocystis with one catalytic domain and four ACT domains per monomer [9]. In this case, dimerization only involves the catalytic domain. However, there are many AKs from whole genomic database,

but minimal crystallographic and biochemical data is available to demonstrate the regulatory principles Avelestat (AZD9668) of structural allostery. Here we report the crystallographic analysis of AK from C. acetobutylicum to a resolution of 3.0 Å in order to define the relationship between the assembly of AKs and the allosteric mechanism of AK, which may be relevant for industrial uses such as the development of effective lysine production strain. The structure of CaAK was determined to 3 Å resolution by single wavelength anomalous dispersion (SAD) method. The crystals belong to the monoclinic space group P21 and forming a total of 576 kDa protein (12 monomers in asymmetric unit with each 48 kDa) which posed the problem of solving the constellation of 108 Se atoms (9 SeMet residues/monomer) in the asymmetric unit.