title: Expression, purification and crystal structure of a truncated acylpeptide hydrolase from Aeropyrum pernix K1.
abstract: Acylpeptide hydrolase (APH) catalyzes the N-terminal hydrolysis of Nalpha-acylpeptides to release Nalpha-acylated amino acids. The crystal structure of recombinant APH from the thermophilic archaeon Aeropyrum pernix K1 (apAPH) was reported recently to be at a resolution of 2.1 Angstrom; using X-ray diffraction. A truncated mutant of apAPH that lacks the first short alpha-helix at the N-terminal, apAPH-delta(1-21), was cloned, expressed, characterized and crystallized. Data from biochemical experiments indicate that the optimum temperature of apAPH is decreased by 15 degrees C with the deletion of the N-terminal alpha-helix. However, the enzyme activity at the optimal temperature does not change. It suggests that this N-terminal alpha-helix is essential for thermostability. Here, the crystal structure of apAPH-delta(1-21) has been determined by molecular replacement to 2.5 Angstrom;. A comparison between the two structures suggests a difference in thermostability, and it can be concluded that by adding or deleting a linking structure (located over different domains), the stability or even the activity of an enzyme can be modified.
authors.affiliation: Laboratory of Structural Biology, Department of Biological Sciences and Biotechnology and Protein Sciences Laboratory of Ministry of Education, Tsinghua University, Beijing 100084, China.
authors.forename: Hai-Feng
authors.initials: HF
authors.lastname: Zhang
authors.forename: Bai-Song
authors.initials: BS
authors.lastname: Zheng
authors.forename: Ying
authors.initials: Y
authors.lastname: Peng
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Lou
authors.forename: Yan
authors.initials: Y
authors.lastname: Feng
authors.forename: Zi-He
authors.initials: ZH
authors.lastname: Rao
mesh_terms: D041522:Aeropyrum / Q000201:enzymology*; D003460:Crystallization; D018360:Crystallography, X-Ray; D004795:Enzyme Stability; D006358:Hot Temperature; D008958:Models, Molecular; D010447:Peptide Hydrolases / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification*; D011487:Protein Conformation; D017433:Protein Structure, Secondary
chemical_list: D010447:Peptide Hydrolases; C038220:acylaminoacyl-peptidase