3BK7

Structure of the complete ABCE1/RNAase-L Inhibitor protein from Pyrococcus abysii

Summary for 3BK7

• Entry DOI: 10.2210/pdb3bk7/pdb
• Related: 1yqt
• Descriptor: ABC transporter ATP-binding protein, MAGNESIUM ION, IRON/SULFUR CLUSTER, ... (5 entities in total)
• Functional Keywords: abc atpase, iron-sulfur cluster, adenosine diphosphate, atp-binding, nucleotide-binding, hydrolyase-translation complex, hydrolyase/translation
• Biological source: Pyrococcus abyssi
• Total number of polymer chains: 1
• Total formula weight: 70490.34

Authors

Karcher, A.,Hopfner, K.P. (deposition date: 2007-12-06, release date: 2007-12-25, Last modification date: 2024-11-13)

Primary citation

Karcher, A.,Schele, A.,Hopfner, K.P.
X-ray Structure of the Complete ABC Enzyme ABCE1 from Pyrococcus abyssi
J.Biol.Chem., 283:7962-7971, 2008

PubMed Abstract: The ATP binding cassette enzyme ABCE1 (also known as RNase-L (ribonuclease L) inhibitor, Pixie, and HP68), one of the evolutionary most sequence-conserved enzymes, functions in translation initiation, ribosome biogenesis, and human immunodeficiency virus capsid assembly. However, its structural mechanism and biochemical role in these processes have not been revealed. We determined the crystal structure of Pyrococcus abyssi ABCE1 in complex with Mg(2+) and ADP to 2.8A resolution. ABCE1 consists of four structural domains. Two nucleotide binding domains are arranged in a head-to-tail orientation by a hinge domain, suggesting that these domains undergo the characteristic tweezers-like powerstroke of ABC enzymes. In contrast to all other known ABC enzymes, ABCE1 has a N-terminal iron-sulfur-cluster (FeS) domain. The FeS domain contains two [4Fe-4S] clusters and is structurally highly related to bacterial-type ferredoxins. However, one cluster is coordinated by an unusual CX(4)CX(3/4)C triad. Surprisingly, intimate interactions of the FeS domain with the adenine and ribose binding Y-loop on nucleotide binding domain 1 suggest a linkage between FeS domain function and ATP-induced conformational control of the ABC tandem cassette. The structure substantially expands the functional architecture of ABC enzymes and raises the possibility that ABCE1 is a chemomechanical engine linked to a redox process.

PubMed: 18160405
DOI: 10.1074/jbc.M707347200

Experimental method

X-RAY DIFFRACTION (2.8 Å)