Summary for 6A0W
| Entry DOI | 10.2210/pdb6a0w/pdb |
| Descriptor | Lipase, SULFATE ION (3 entities in total) |
| Functional Keywords | rhizopus microsporus var. chinensis, lipase, n-terminal polypeptide segment, hydrolase |
| Biological source | Rhizopus chinensis (Bread mold) |
| Total number of polymer chains | 1 |
| Total formula weight | 33651.71 |
| Authors | Zhang, M.,Yu, X.W.,Xu, Y.,Huang, C.H.,Guo, R.T. (deposition date: 2018-06-06, release date: 2019-10-09, Last modification date: 2024-11-06) |
| Primary citation | Zhang, M.,Yu, X.W.,Xu, Y.,Guo, R.T.,Swapna, G.V.T.,Szyperski, T.,Hunt, J.F.,Montelione, G.T. Structural Basis by Which the N-Terminal Polypeptide Segment ofRhizopus chinensisLipase Regulates Its Substrate Binding Affinity. Biochemistry, 58:3943-3954, 2019 Cited by PubMed Abstract: Members of an important group of industrial enzymes, lipases, exhibit valuable hydrolytic features that underlie their biological functions. Particularly important is their N-terminal polypeptide segment (NTPS), which is required for secretion and proper folding but is removed in the process of enzyme maturation. A second common feature of this class of lipases is the α-helical "lid", which regulates the accessibility of the substrate to the enzyme active site. Some lipases also exhibit "interfacial activation" by micelle and/or aggregate surfaces. While it has long been recognized that the NTPS is critical for function, its dynamic features have frustrated efforts to characterize its structure by X-ray crystallography. Here, we combine nuclear magnetic resonance spectroscopy and X-ray crystallography to determine the structure and dynamics of lipase (RCL) with its 27-residue NTPS prosequence (r27RCL). Both r27RCL and the truncated mature form of RCL (mRCL) exhibit biphasic interfacial activation kinetics with -nitrophenyl butyrate (NPB). r27RCL exhibits a substrate binding affinity significantly lower than that of mRCL due to stabilization of the closed lid conformation by the NTPS. In contrast to previous predictions, the NTPS does not enhance lipase activity by increasing surface hydrophobicity but rather inhibits activity by forming conserved interactions with both the closed lid and the core protein structure. Single-site mutations and kinetic studies were used to confirm that the NTPS serves as internal competitive inhibitor and to develop a model of the associated process of interfacial activation. These structure-function studies provide the basis for engineering RCL lipases with enhanced catalytic activities. PubMed: 31436959DOI: 10.1021/acs.biochem.9b00462 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2 Å) |
Structure validation
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