Description

IPR008930 is a Terpenoid cyclases/protein prenyltransferase alpha-alpha toroid.

<p>Protein prenyltransferases catalyse the transfer of the carbon moiety of C15 farnesyl pyrophosphate or geranylgeranyl pyrophosphate synthase to a conserved cysteine residue in a CaaX motif of protein and peptide substrates. The addition of a farnesyl group is required to anchor proteins to the cell membrane. In the 3D structure of a mammalian Ras farnesyltransferases (Ftase), both subunits are largely composed of α-helices. The α2 to α15 helices in the alpha subunit fold into a novel helical hairpin structure, resulting in a crescent-shape domain that envelopes part of the subunit. The 12 helices of the beta-subunit form an α-α barrel. Six additional helices connect the inner core of helices and form the outside of the helical barrel. A deep cleft surrounded by hydrophobic amino acids in the centre of the barrel is proposed as the FPP-binding pocket. A single Zn2+ ion is located at the junction between the hydrophilic surface groove near the subunit interface [[cite:PUB00100418], [cite:PUB00100416], [cite:PUB00100417], [cite:PUB00010618]].</p> <p>Terpenoid cyclases such as squalene cyclase, pentalenene synthase, 5-epi-aristolochene synthase, and trichodiene synthase are responsible for the synthesis of cholesterol, a hydrocarbon precursor of the pentalenolactone family of antibiotics, a precursor of the antifungal phytoalexin capsidiol, and the precursor of antibiotics and mycotoxins, respectively. In the structures of these three enzymes, the similar structural feature referred to as 'terpenoid synthase fold' with 10-12 mostly antiparallel α-helices is found, as also observed in protein prenyltransferases. The high structural similarity provides support for the hypothesis that the three families of prenyltransferases have related evolution despite their low sequence similarity [[cite:PUB00010618]].</p> <p>Alpha-2-macroglobulin inhibit all four classes of proteinases by a unique 'trapping' mechanism in which the inhibitor undergoes global structural transformation to lead active proteases into its molecular cage. It also shows other functions related with the immune-cell function such as the binding of cytokines or the facilitation of cell migration [[cite:PUB00100415], [cite:PUB00100414]].</p>

This description is obtained from EB-eye REST.

Associated GO terms

Unable to find any GO terms for the transcript with the identifier.

Associated Lotus transcripts 124

Co-occuring domains 1

A list of co-occurring predicted domains within the L. japonicus gene space: