MOLYBDENUM COFACTOR BIOSYNTHESIS IN NEUROSPORA-CRASSA - BIOCHEMICAL-CHARACTERIZATION OF PLEIOTROPIC MOLYBDOENZYME MUTANTS NIT-7, NIT-8 NIT-9A, NIT-9B AND NIT-9C

被引：11

作者：

HECK, IS ^{[1
]}

NINNEMANN, H ^{[1
]}

机构：

[1] UNIV TUBINGEN,INST CHEM PFLANZENPHYSIOL PFLANZENBIOCHEM,D-72076 TUBINGEN,GERMANY

来源：

PHOTOCHEMISTRY AND PHOTOBIOLOGY | 1995年 / 61卷 / 01期

关键词：

D O I：

10.1111/j.1751-1097.1995.tb09242.x

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Available mutants of molybdenum cofactor (MoCo) biosynthesis of Neurospora crassa were studied for converting factor activity and for in vitro molybdate repair of nitrate reductase (NR) activity. Mutant nit-7 was found to contain an activity that fits the functional definition of converting factor activity in Escherichia coli. Its high molecular weight fraction converts a low molecular weight compound from nit-1 and nit-8 into biologically active molybdopterin (MPT). Like nit-1, mutant nit-8 is devoid of this activity. Mutants nit-9 A, B and C contain a protein-bound precursor form of MoCo, which is presumed to be MPT bound to apo-NR. It is converted into active MoCo as part of NR in the presence of reduced glutathione and high exogenous molybdate concentrations. The NR apoenzyme of nit-1 is needed to detect the total amount of MoCo after molybdate repair, because mutants nit-g A, B and C build no detectable content of functional NR apoenzyme. Evidence is presented for the transfer of MPT from demolybdo-NR to free NR apoenzyme.

引用

页码：54 / 60

页数：7

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