Structure of the Substrate Binding Pocket of the Multidrug Transporter EmrE:  Site-Directed Spin Labeling of Transmembrane Segment 1†

Biochemistry ◽  
2003 ◽  
Vol 42 (20) ◽  
pp. 6099-6105 ◽  
Author(s):  
Hanane A. Koteiche ◽  
Matthew D. Reeves ◽  
Hassane S. Mchaourab
Keyword(s):  
Substrate Binding ◽  
Binding Pocket ◽  
Spin Labeling ◽  
Multidrug Transporter ◽  
Transmembrane Segment ◽  
Substrate Binding Pocket ◽  
Site Directed Spin Labeling

scholarly journals Crystal structure of steroid reductase SRD5A reveals conserved steroid reduction mechanism

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yufei Han ◽  
Qian Zhuang ◽  
Bo Sun ◽  
Wenping Lv ◽  
Sheng Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Biochemical Characterization ◽  
Substrate Binding ◽  
Binding Pocket ◽  
Substrate Binding Pocket ◽  
Transmembrane Segments ◽  
Therapeutic Molecules ◽  
Binding Cavity ◽  
Immune System Regulation ◽  
Mediated Reduction

AbstractSteroid hormones are essential in stress response, immune system regulation, and reproduction in mammals. Steroids with 3-oxo-Δ4 structure, such as testosterone or progesterone, are catalyzed by steroid 5α-reductases (SRD5As) to generate their corresponding 3-oxo-5α steroids, which are essential for multiple physiological and pathological processes. SRD5A2 is already a target of clinically relevant drugs. However, the detailed mechanism of SRD5A-mediated reduction remains elusive. Here we report the crystal structure of PbSRD5A from Proteobacteria bacterium, a homolog of both SRD5A1 and SRD5A2, in complex with the cofactor NADPH at 2.0 Å resolution. PbSRD5A exists as a monomer comprised of seven transmembrane segments (TMs). The TM1-4 enclose a hydrophobic substrate binding cavity, whereas TM5-7 coordinate cofactor NADPH through extensive hydrogen bonds network. Homology-based structural models of HsSRD5A1 and -2, together with biochemical characterization, define the substrate binding pocket of SRD5As, explain the properties of disease-related mutants and provide an important framework for further understanding of the mechanism of NADPH mediated steroids 3-oxo-Δ4 reduction. Based on these analyses, the design of therapeutic molecules targeting SRD5As with improved specificity and therapeutic efficacy would be possible.

Characterization of the Acyl Substrate Binding Pocket of Acetyl-CoA Synthetase†

Biochemistry ◽  
2006 ◽  
Vol 45 (38) ◽  
pp. 11482-11490 ◽  
Author(s):  
Cheryl Ingram-Smith ◽  
Barrett I. Woods ◽  
Kerry S. Smith
Keyword(s):  
Substrate Binding ◽  
Binding Pocket ◽  
Substrate Binding Pocket ◽  
Acetyl Coa

scholarly journals The Hydrophobic Hinge Region of Rat DNA Polymerase β Is Critical for Substrate Binding Pocket Geometry

2005 ◽  
Vol 280 (31) ◽  
pp. 28388-28393 ◽  
Author(s):  
Daniela Starcevic ◽  
Shibani Dalal ◽  
Joachim Jaeger ◽  
Joann B. Sweasy
Keyword(s):  
Dna Polymerase ◽  
Substrate Binding ◽  
Binding Pocket ◽  
Hinge Region ◽  
Dna Polymerase Β ◽  
Substrate Binding Pocket

scholarly journals The endoplasmic reticulum P5A-ATPase is a transmembrane helix dislocase

Science ◽  
2020 ◽  
Vol 369 (6511) ◽  
pp. eabc5809 ◽  
Author(s):  
Michael J. McKenna ◽  
Sue Im Sim ◽  
Alban Ordureau ◽  
Lianjie Wei ◽  
J. Wade Harper ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Targeting ◽  
Transmembrane Helix ◽  
Protein Composition ◽  
Binding Pocket ◽  
Transmembrane Segment ◽  
Substrate Binding Pocket ◽  
Cryo Electron Microscopy ◽  
Endogenous Substrate ◽  
P Type

Organelle identity depends on protein composition. How mistargeted proteins are selectively recognized and removed from organelles is incompletely understood. Here, we found that the orphan P5A–adenosine triphosphatase (ATPase) transporter ATP13A1 (Spf1 in yeast) directly interacted with the transmembrane segment (TM) of mitochondrial tail–anchored proteins. P5A-ATPase activity mediated the extraction of mistargeted proteins from the endoplasmic reticulum (ER). Cryo–electron microscopy structures of Saccharomyces cerevisiae Spf1 revealed a large, membrane-accessible substrate-binding pocket that alternately faced the ER lumen and cytosol and an endogenous substrate resembling an α-helical TM. Our results indicate that the P5A-ATPase could dislocate misinserted hydrophobic helices flanked by short basic segments from the ER. TM dislocation by the P5A-ATPase establishes an additional class of P-type ATPase substrates and may correct mistakes in protein targeting or topogenesis.

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