Reddy C A, D'Souza T M
Department of Microbiology, Michigan State University, East Lansing 48824-1101.
FEMS Microbiol Rev. 1994 Mar;13(2-3):137-52. doi: 10.1111/j.1574-6976.1994.tb00040.x.
The white-rot basidiomycete Phanerochaete chrysosporium produces lignin peroxidases (LiPs), a family of extracellular glycosylated heme proteins, as major components of its lignin-degrading system. Up to 15 LiP isozymes, ranging in M(r) values from 38,000 to 43,000, are produced depending on culture conditions and strains employed. Manganese-dependent peroxidases (MnPs) are a second family of extracellular heme proteins produced by P. chrysosporium that are also believed to be important in lignin degradation by this organism. LiP and MnP production is seen during secondary metabolism and is completely suppressed under conditions of excess nitrogen and carbon. Excess Mn(II) in the medium, on the other hand, suppresses LiP production but enhances MnP production. Nitrogen regulation of LiP and MnP production is independent of carbon and Mn(II) regulation. LiP activity is also affected by idiophasic extracellular proteases. Intracellular cAMP levels appear to be important in regulating the production of LiPs and MnPs, although LiP production is affected more than MnP production. Studies on the sequencing and characterization of lip cDNAs and genes of P. chrysosporium have shown that the major LiP isozymes are each encoded by a separate gene. Each lip gene encodes a mature protein that is 343-344 amino acids long, contains 1 putative N-glycosylation site, a number of putative O-glycosylation sites, and is preceded by a 27-28-amino acid leader peptide ending in a Lys-Arg cleavage site. The coding region of each lip gene is interrupted by 8-9 introns (50-63 bp), and the positions of the last two introns appear to be highly conserved. There are substantial differences in the temporal transcription patterns of the major lip genes. The sequence data suggest the presence of three lip gene subfamilies. The genomic DNA of P. chrysosporium strain BKMF-1767 was resolved into 10 chromosomes (genome size of 29 Mb), and that of strain ME-446 into 11 chromosomes (genome size of 32 Mb). The lip genes have been localized to five chromosomes in BKMF-1767 and to four chromosomes in ME-446. DNA transformation studies have reported both integrative and non-integrative transformation in P. chrysosporium.
白腐担子菌黄孢原毛平革菌产生木质素过氧化物酶（LiP），这是一族细胞外糖基化血红素蛋白，是其木质素降解系统的主要成分。根据培养条件和所用菌株的不同，可产生多达15种LiP同工酶，其相对分子质量在38,000至43,000之间。锰依赖过氧化物酶（MnP）是黄孢原毛平革菌产生的第二类细胞外血红素蛋白，也被认为在该生物体的木质素降解过程中起重要作用。LiP和MnP的产生出现在次级代谢过程中，在过量氮和碳的条件下会被完全抑制。另一方面，培养基中过量的Mn（II）会抑制LiP的产生，但会增强MnP的产生。LiP和MnP产生的氮调节独立于碳和Mn（II）调节。LiP活性也受分化期细胞外蛋白酶的影响。细胞内cAMP水平似乎在调节LiP和MnP的产生中起重要作用，尽管LiP的产生比MnP的产生受影响更大。对黄孢原毛平革菌lip cDNA和基因的测序及特性研究表明，主要的LiP同工酶各自由一个单独的基因编码。每个lip基因编码一个成熟蛋白，该蛋白长度为343 - 344个氨基酸，含有1个假定的N - 糖基化位点、多个假定的O - 糖基化位点，并且前面有一个以赖氨酸 - 精氨酸切割位点结尾的27 - 28个氨基酸的前导肽。每个lip基因的编码区被8 - 9个内含子（50 - 63 bp）中断，最后两个内含子的位置似乎高度保守。主要lip基因的时间转录模式存在显著差异。序列数据表明存在三个lip基因亚家族。黄孢原毛平革菌菌株BKMF - 1767的基因组DNA被解析为10条染色体（基因组大小为29 Mb），菌株ME - 446的基因组DNA被解析为11条染色体（基因组大小为32 Mb）。lip基因已定位到BKMF - 1767的5条染色体和ME - 446的4条染色体上。DNA转化研究报道了黄孢原毛平革菌中的整合型和非整合型转化。
