1QB2

CRYSTAL STRUCTURE OF THE CONSERVED SUBDOMAIN OF HUMAN PROTEIN SRP54M AT 2.1A RESOLUTION: EVIDENCE FOR THE MECHANISM OF SIGNAL PEPTIDE BINDING

Summary for 1QB2

• Entry DOI: 10.2210/pdb1qb2/pdb
• Descriptor: HUMAN SIGNAL RECOGNITION PARTICLE 54 KD PROTEIN (2 entities in total)
• Functional Keywords: alpha-helix, helix-turn-helix, signaling protein
• Biological source: Homo sapiens (human)
• Cellular location: Nucleus speckle : P61011
• Total number of polymer chains: 2
• Total formula weight: 24946.88

Authors

Clemons Jr., W.M.,Gowda, K.,Black, S.D.,Zwieb, C.,Ramakrishnan, V. (deposition date: 1999-04-29, release date: 1999-10-20, Last modification date: 2024-02-14)

Primary citation

Clemons Jr., W.M.,Gowda, K.,Black, S.D.,Zwieb, C.,Ramakrishnan, V.
Crystal structure of the conserved subdomain of human protein SRP54M at 2.1 A resolution: evidence for the mechanism of signal peptide binding.
J.Mol.Biol., 292:697-705, 1999

PubMed Abstract: Protein SRP54 is an integral part of the mammalian signal recognition particle (SRP), a cytosolic ribonucleoprotein complex which associates with ribosomes and serves to recognize, bind, and transport proteins destined for the membrane or secretion. The methionine-rich M-domain of protein SRP54 (SRP54M) binds the SRP RNA and the signal peptide as the nascent protein emerges from the ribosome. A focal point of this critical cellular function is the detailed understanding of how different hydrophobic signal peptides are recognized efficiently and transported specifically, despite considerable variation in sequence. We have solved the crystal structure of a conserved functional subdomain of the human SRP54 protein (hSRP54m) at 2.1 A resolution showing a predominantly alpha helical protein with a large fraction of the structure available for binding. RNA binding is predicted to occur in the vicinity of helices 4 to 6. The N-terminal helix extends significantly from the core of the structure into a large but constricted hydrophobic groove of an adjacent molecule, thus revealing molecular details of possible interactions between alpha helical signal peptides and human SRP54.

PubMed: 10497032
DOI: 10.1006/jmbi.1999.3090

Experimental method

X-RAY DIFFRACTION (2.1 Å)