1n7k

From Proteopedia

Unique tetrameric structure of deoxyribose phosphate aldolase from Aeropyrum pernix

Overview

A gene encoding a 2-deoxy-d-ribose-5-phosphate aldolase (DERA) homolog was, identified in the hyperthermophilic Archaea Aeropyrum pernix. The gene was, overexpressed in Escherichia coli, and the produced enzyme was purified, and characterized. The enzyme is an extremely thermostable DERA; its, activity was not lost after incubation at 100 degrees C for 10 min. The, enzyme has a molecular mass of approximately 93 kDa and consists of four, subunits with an identical molecular mass of 24 kDa. This is the first, report of the presence of tetrameric DERA. The three-dimensional structure, of the enzyme was determined by x-ray analysis. The subunit folds into an, alpha/beta-barrel. The asymmetric unit consists of two homologous, subunits, and a crystallographic 2-fold axis generates the functional, tetramer. The main chain coordinate of the monomer of the A. pernix enzyme, is quite similar to that of the E. coli enzyme. There was no significant, difference in hydrophobic interactions and the number of ion pairs between, the monomeric structures of the two enzymes. However, a significant, difference in the quaternary structure was observed. The area of the, subunit-subunit interface in the dimer of the A. pernix enzyme is much, larger compared with the E. coli enzyme. In addition, the A. pernix enzyme, is 10 amino acids longer than the E. coli enzyme in the N-terminal region, and has an additional N-terminal helix. The N-terminal helix produces a, unique dimer-dimer interface. This promotes the formation of a functional, tetramer of the A. pernix enzyme and strengthens the hydrophobic, intersubunit interactions. These structural features are considered to be, responsible for the extremely high stability of the A. pernix enzyme. This, is the first description of the structure of hyperthermophilic DERA and of, aldolase from the Archaea domain.

About this Structure

1N7K is a Single protein structure of sequence from Aeropyrum pernix. Active as Deoxyribose-phosphate aldolase, with EC number 4.1.2.4 Full crystallographic information is available from OCA.

Reference

The first crystal structure of archaeal aldolase. Unique tetrameric structure of 2-deoxy-d-ribose-5-phosphate aldolase from the hyperthermophilic archaea Aeropyrum pernix., Sakuraba H, Tsuge H, Shimoya I, Kawakami R, Goda S, Kawarabayasi Y, Katunuma N, Ago H, Miyano M, Ohshima T, J Biol Chem. 2003 Mar 21;278(12):10799-806. Epub 2003 Jan 15. PMID:12529358

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